Myths in cycling: wider tires are slower | Hacker News Reader

Myths in cycling: wider tires are slower

renehersecycles.com

419 pointsjmilloy405 comments

This is one of the reasons I love the emergence of the "Gravel" category of bikes. They look and have geometry similar to a road bike, but they have enough clearance for nice fat gravel tires.

I ride in Chicago (shitty roads, potholes & construction are everywhere), and love that I can put nice 38mm+ GravelKing Slick tires on the bike, and still have no problem keeping up with most road bikes. I've gotten funny looks from folks who're unfamiliar with the concept, but it's such a great setup.

Comfy/soft ride too.

Edit: Cannondale Topstone if anyone is curious.

My bike is the best for the city.. got a Specialized Tri-Cross with 32mm tires.. can do everything and handle our horrible roads.

Yeah, my roady friends are jealous because I get to use my gravelbike off-road, and my mountainbike friends are jealous at me for being able to keep up with roadies. And all that for the price of one bike and an extra set of wheels with slicks!

Canyon Grail here, yes the one with the weird cockpit :)

How off-road do you go? I have a gravel bike too, but I much prefer the MTB for rocky descents.

I also own a Canyon Grail (the alloy one, so no weird handlebar) and it's pretty capable for fire roads and some singletrack. When it gets really rocky and rooty though I find myself having less fun simply because the riding experience becomes so jarring and rattly. It's also way more fun to climb on (as in you actually enjoy the climbs as opposed to just doing them to get to the downhills) compared to a mountain bike. Where I live I have to ride ~7 miles each way to get to the trails so it makes a lot of sense as my one off-road bike.

Yeah some of the gravel bike stuff really amazes me these days. I can't imagine doing some descents on anything but a fireroad with a gravel bike due to the un-slack geometry, but I've seen people bomb green downhill runs at some bike parks!

Mostly just normal gravel roads and forest paths. I have done some very light MTB trails (here in the flatter than flat Netherlands), and did some touring through the German Eifel (that was intense!) and the Belgian Ardennes.

For me it's al about having the freedom to go where I feel like going in the moment and not having to worry too much about gear. For me this bike is like the golden mean, but there are other gravel bikes with slightly more clearance or better shock absorption if you're looking to take it on slightly more intense trips.

Here's a quirky gravel-centric YouTube channel I came across a while back: https://www.youtube.com/channel/UCV9WtB_q5sJfe3Rev5PWy-Q

Similarly in the motorcycle world, dual sport and adventure models originally designed for on road/off road mix are now quite popular as commuter machines. Their long suspension makes them quite comfortable over potholes, cracks, curbs and generally poor road surfaces. And many models are narrow enough to filter between lanes with ease.

I would argue that "designed for [off] road mix" is pretty charitable. A 500-pound dirt bike with a comfortable seating position wins the tough-aesthetics competition, but off road performance is meager at best. I built decent off-road skills on a DL1000, but the weight was always such a liability as to make it impracticable. I moved to a smaller and lighter bike and have more fun, but 99% of people I met in Arizona are happy with their big ADV bikes— with zero interest in going off road.

I think the most interesting take-away is that there is a segment of people who value being given an excuse for something rugged— I heard lots of "I just like the peace-of-mind that I could go anywhere if I needed to" whether they believe themselves or not.

Well there's shades of grey between paved tarmac and proper off road.

Not a motorcyclists but I assume these adventure/dual sport bikes perform much better over say unsealed roads, and are at least workable on fire roads.

Fire roads are easy mode on an ADV bike. They can do double track quite well too. They start to struggle in mud, sand and single track.

I'd presume that pure street motorcycles would fair pretty badly on even double track.

So yeah, ADV would seem to be useful for something other than wanting to look rugged.

This is exactly right. The contrast that piqued my interest was something like knobby tires on a heavy bike that spent its life on the street. Turns out people value comfort (here, seating position and long suspension travel), but those things only seem to sell with a rugged aesthetic. Balancing these needs is something of a Hard Problem, so it's interesting to watch this play out throughout the industry.

Totally, in London i regularly encounter cobbled streets, my big tyre gravel bike is perfect.

Even on a street only trip I'd prefer an adventure bike to most street bikes, the rugged factor shouldn't be discounted when you're 1000+ miles away from home and outside of cell signal.

You'd be surprised. I've taken my 500-pound dirt bike (KTM 990A) to the end of Baja (all dirt), across the Trans America Trail, and to Alaska and back. Did most of the hard splits on LA-Barstow-to-Vegas a few years ago, and endless dirt riding in the Sierras and Nevada. And I'm by no means the best rider I know.

Single track is hard work but there's nothing quite like ripping open the throttle on a 100hp dirt bike and throwing up a tornado of sand. I owned an XR250R for a few years and just found it boring.

To be fair the VStrom 1000 the commentor was riding is fairly heavy and street oriented. A KTM, Tenere or smaller GS blows it out of the water off road.

I've ridden with some others on big KTMs who struggle a lot more than the guys on the smaller bikes. I think once a certain weight threshold is crossed there's no argument that the bike is appropriately called an "off-road" bike, no matter how knobby the tires. Conversely, aesthetics are always in play. Especially for the GS guys at Starbucks ;)

I see those dual sports all the time and I don't see the attraction other than image. They're less agile on-road which is where they spend their time. At least they're not as silly as the trend of sticking knobbly tyres on road bikes for that "scrambler" look.

If anything the opposite trend makes more sense, the motard / supermotard style where a competent off-road bike is retrofitted with road tyres and suspension tuning. They look like an absolute blast.

Dual sports can usually withstand a few drops with nothing more than new levers, parts are cheap, and maintenance is usually easier than street bikes. I almost always recommend a small dual sport as a first bike. If you get a used one for a decent price you can almost always sell it for what you paid for it even if it takes a couple of tumbles, and you can see if you like off-road too.

>At least they're not as silly as the trend of sticking knobbly tyres on road bikes for that "scrambler" look.

FWIW I've got a mid-weight streetfighter that I'd love to put some 50/50 tires and a skid plate on. But I already take it into the dirt so it would be an improvement.

And yes, supermotos might be the ultimate motorcycle.

Would like to jump on this comment to agree with you.

A buddy of mine dropped his s1000rr coming out of a right turn at a traffic light and was up for around $8k in damages... He was only going ~10mph. I envy those who can fix their bikes after dropping them for $20 when they didn't even have frame sliders etc.

Yeah, I ride a semi-naked and as my first 'big bike' (I've had it nearly a decade, though) it's been dropped a couple of times, with only a couple of scuffs on the crankcase to show for it. Definitely a big consideration!

This is only true if you keep the 21” front when and then only if you are trying to keep up with skilled riders (disclaimer I’m not the average rider). Had a dual sport that I made into a super moto with ultra stick rubber. Would blow away a GSXR/Ducati/R1/R6 on HWY 9 all the windy sections. Those bikes could out accelerate me on straights but they all held me up in corners.

I had an absolute blast on my Yamaha XT660X, which was sort of a motard version of a dual-sport. Small and light for an adventure bike, but a bit too large and heavy to be a true supermoto.

660cc single-cylinder that you could just beat on all day without breaking the law too much, plus super long suspension travel and fat sticky road tires made for a bike that just ate up speed bumps and rough roads. I pulled some gnarly wheelies over bumps and cresting hills, so much fun.

And it was obnoxiously orange, I loved that bike. It was a shame someone else decided that he liked it more and cut though a massive Kryptonite chain to get it.

Yeah, when I first got my gravel bike I thought I'd be sacrificing some road performance for better flexibility and comfort, but that didn't happen. The actual result was that my times on smooth segments were unchanged and I've beaten many of my personal bests on rougher roads (and obviously it's much better on dirt).

It's not a perfectly fair comparison because I did upgrade to a nicer bike in the process, but my previous bike was already into the territory of significant diminishing returns for someone who doesn't race and doesn't actually care about saving seconds.

I ended up commuting on my big tire bike because it's so much more comfortable and just as quick.

Don't gravel bikes have much smaller gear ratios? There is no way a strong road cyclist would have the same times on a gravel bike as a road bike purely due to the size of the front chain ring. I run a semi-compact up front on my road bike and I can't go faster than 53kmh on the flat without my cadence getting too high to sustain for longer periods of time.

I don't think the difference is that large, but there is some. I haven't tried myself, but would be interesting to test it against each other.

You can compare gearing ratios on 99spokes, e.g. https://99spokes.com/compare?bikes=scott-speedster-gravel-20...

I've been road riding with people who switched to gravel bikes and they were suddenly noticeably slower. They also seemed to run out of gas earlier which means they were expending more energy to keep up.

Weren't those new bikes heavier?

My own road bike is nothing particularly fancy, but it's very light. Just because those bikes may be made to take more of a beating than a road-bike, they may be heavier. I'm thinking in particular tougher wheels and front work, possibly the whole frame.

We were riding on mostly flat terrain so it wouldn't be a big differentiator.

Were they using tires without any tread?

interesting, maybe different frame geometry contributed as well?

I would imagine this would be considerable. Improving your aero position is the easiest way to go faster.

You could put a road groupset on most gravel frames.

Serious gravel racers definitely run more "road-like" ratios

If you can spin out a 50x11 or similar on the flat you're in a very small minority of cyclists...

I'm not spinning out but I am spinning faster than I can sustain / is efficient. I'm looking for the next gear basically. Spinning out is much faster and requires and descent (for me at least). Based on Strava I'm not that strong. Top 40% maybe. If I was racing I'd be cat 4. My observation is more to do with stronger riders than I am. Once you get to a certain speed/ftp all the considerations like rolling resistance, gearing, aero etc become much more obvious. If you are averaging 29.5km/h like in the test you might think optimisations don't make much difference but if you average 40kmh+ you will know they do.

They even note this in the article "If you ride much faster, then it’s possible that wider tires have a little more wind resistance, but the difference will be so small that it’ll get lost in all the other factors that influence your bike’s speed. On the other hand, if you ride slower, then the advantage of wider tires will be even greater."

Not much smaller, 46/30 crank instead of 50/34 and maybe 34 or 36 rear cogs instead of 28 or 32.

My 2019 Trek Crossrip has 48/32 and 11-32. Of course, you could switch those components up - the biggest difference between gravel and road is the clearance for wider tires, and "relaxed" or upright geometry, plus capability for more mounting.

And Cannondale even has a carbon frame with a front suspension and rear flex on the frame for a near-full-suspension behavior.

I run out of gears on flat terrain but that is a negligible portion of what I ride. I'd definitely expect a gravel bike to be a bigger handicap if you're riding mostly flat terrain and actually care about your speed on those sections.

Slicks themselves are under-appreciated.

I bought a Specialized Diverge over a year ago. It was mostly to commute to and from work, but also to have the ability to take gravel paths and trails on the weekends. It's been awesome but friends have suggested I take off the stock tires and add some new ones. Is it really worth it? The tires are already fairly fat already, at least compared to road bike tires.

The Diverge was on my shortlist when I got the Topstone. At the time (2019), I think the Diverge defaulted to skinnier smoother tires. Can’t remember which tires specifically.

The Topstone shipped with some pretty knobby WTBs that definitely had an impact on rolling resistance. If your tires are knobby/optimized for off-road, putting a slicker tire (the GK slicks are quite popular for good reason), I suspect you’ll notice quite a difference, but I’d look more at the knobbiness than the fatness if you’re considering a change.

Also worth noting that some knobby tires have a hard line down the middle that keeps resistance minimal until you start to turn, at which point you hit the high traction portion of the tire. Takeaway: even if it looks knobby, it might not be as slow as it looks.

32mm+ is already getting into “fat” territory for a road bike, and for me personally, 38mm seems to be my sweet spot.

They came with 35mm "roadsport flak jacket" https://www.specialized.com/us/en/roadsport/p/155765?color=2....

They're pretty smooth overall, perhaps why I never really had an issue commuting with them, but I'm always looking to go faster!

Found the details - I went from 40mm WTB Nanos [0] to these 38mm GravelKing Slicks [1]. If you look at the product pages, the difference is pretty striking. I don't know much about the RoadSports, but at least when it comes to "slick-ness", it looks like you're already starting from a slicker baseline than I was.

- [0] https://www.wtb.com/products/nano-40c

- [1] https://www.panaracerusa.com/products/gravelking-slick-foldi...

You could try Gravelking slicks which are fast and still grippy or Conti GP5000s which are very fast.

I have enjoyed the WTB Trailblazers as they are knobby enough to run singletrack but have a solid centerline for touring longevity and better rolling resistance. You just have to adjust the tire pressure according to what you're predominantly doing that day. Commutting I run them at 35-45psi and on the trail I run them at 18-22psi no worries.

The Pathfinder tires that come stock on recent Diverges are pretty widely regarded as not just the worst part of the bike, but a sort of bafflingly bad choice because they aren't even cheap. If you're looking to spend some money upgrading your bike, they're a good place to start.

I've got about 500 miles on my Diverge (and the Pathfinders) the tires ride great.

- Good on the road, even cornering is decent which was unexpected with light tread.

- Great on gravel: flat, uphill, downhill, and cornering

- Decent on single track

I think maybe they get a bad rap because they are on the heavy side for the price? When the time comes for new tires not sure if I will get another pair or try out something different.

Really? Loads of Unbound Gravel finishers were on Pathfinders.

If they’re causing you problems, consider replacing them. Otherwise I’d just wait until you get a flat — no point in spending money on something which isn’t a problem. You’re commuting so you’re reliably putting on mileage without [presumably] getting in to dodgy situations or trying to shave every second or gram off.

I think tires affect the ride quality and comfort and speed more than any other easy to replace component. Even if you don't go any wider, the supple tires from Rene Herse really blew me away. I think it's worth it, or just waint until you have to replace the tires anyways.

I got my Cannondale CAADX in 2015 right before the gravel hype started. I've put WTB Riddler 37 on it and it's close to a gravel bike but a bit more direct and maneuverable - I love it. If I was in for a new bike right now, I'd be very tempted to get a Canyon Grail with electronic shifting though. After Cannondale's manufacturing error put me in the hospital for a night followed by a broad recall of a lot of their carbon fiber forks and they new minimalist logo I'm just not a fan of Cannondale anymore. But the Topstone is a great bike!

Sorry to hear that you were affected by the fork defect. I hope there were no lasting effects from the injuries.

I got Cannondale's recall email as I was flying to Kenya, with my CAADX, for a cycling trip. Was a bit nervous riding the bike, especially given the terrain, but in the end decided to risk it as I didn't want to curtail the trip.

At the time I was wondering whether I was overreacting, and decided that I probably was. It is quite shocking to come across someone who personally suffered an accident due to the fault.

I used to ride thin-tire road bikes but a year ago I bought a Mercier Kilo WT (WT is for "wide tire") which is a light road frame with a fork that allows beefy gravel tires. I don't think I'll go back to thin-tire road bikes.

My only complaint about the gravel trend is that at the entry (and mid) level they are often using pretty crappy disc brakes when rim brakes would have been a better choice in 90% of cases. When they are hydraulic, they are a dream to use, but with a cable you really lose the brake feel.

Ha! I only figured it out after buying Kona Rove NRB, which is not even an entry-level bike, but it turned out to have disk brakes and extremely fragile paintwork.

It served me well, but I am still somewhat cautious when descending since then.

I’m glad to see another Rove owner mention the paint. I swear wiping sweat off the top tube scrapes through the paint.

Mechanical disk brakes, I mean.

Rim brakes on roadbikes are awesome, but they are awesome because the calipers don't have to go far around the tire. If you try to build them for wider tires you suffer far more flex and flex means that you can't pull a high lever transmission ratio before running out of lever movement. Remember "brake boosters" on cantilever brakes? Same problem, the requirement to transfer the counterforce far around the tire. I'm a rim brake die-hard, but for anything wider than 28 go disc.

The only caveat is carbon wheels. I hate rim brakes on carbon wheels,they legitimately suck and disc is way better for that application.

I actually just sold my carbon wheels and downgraded back to aluminium until I buy a disc bike for the long term.

Rim breaking on deep dish tempo wheels sounds horrifying.

They are certainly not the kind of wheels you'd want to use on steep roads with unpredictable weather (e.g. because the trip was planned months in advance and the bike), anybody into that kind of toy usually keeps a set of low section wheels for those occasions (or bike/bikes, if the looks just don't match). Disc brake doesn't change that by the way, because crosswinds can be brutal in the mountains.

Discs solve my issue because 40mm deep is enough to not suffer from terrible crosswinds, if the wheels are made well.

The worst problem is after a few minutes of constant breaking, which you have to do if you're descending a mountain carefully and care for your life, the rim brakes on carbon start to squeal and you lose a lot of braking power. You also used to risk delamination but that isn't that big of an issue on the newer wheels.

I'd had just about every cable actuated brakes. Old school cantilevers, various flavors, u-brakes, v-brakes, cable-discs etc. etc. etc.

Didn't realize what I was missing till I tried a nice set of hydraulic discs, I'll never go back.

That list is looking suspiciously void of brakes that would have trouble fitting a 28 mm tire. Yes, disc brakes can be very good, but the gap is much smaller than must people would expect.

Heh, I've had my fair share that would hit the limit in the 25-28mm. In particular the shimano SLR/dual action/dual lever or whatever they are called.

I don't agree with the "gap is much smaller than people would expect". Have you tried a decent hydraulic brake? I raced on and off road, was a bike messenger, designed and built (from tubes) a mtb frame, and bike commuted nearly every workday of my life. Disc brakes have significant advantages over any rim brake.

Don't knock them till you try them, I was dubious myself.

Heh, I don't doubt that they are powerful and I sure won't bend over backwards to still get rim brakes next time I want/need a bike, but the "want" isn't exactly strengthened by the switch. And yes, even aluminium wheels aren't really a joy decelerating in the rain (and yes, I've been to that group ride where one guy could show off his nice new aero carbon toy while my nice new aero carbon toy had to stay at home because for a dozen hours of mostly rain as a rim rider your choice will definitely fall on the one with the aluminium wheels. I guess I just can't warm up to the idea of front wheels with twentysomething spokes. It's confusing enough already that carbon front wheels (for rim) almost universally come with 18 instead of 16, what's up with that?

Er, not sure on the spokes. Why not use 18? Is 16 better somehow? I'm over 200 pounds and am hard on wheels, I've been pretty happy with Santa Cruz carbons, which in the road flavor are 24 spokes.

Indeed! In the same series: Myth: disc brakes work better than rim brakes[0]. The rim is the rotor of a bit disc brake rotor that cools better and doesn't add any weight. But the wider tires make disc brakes a necessary choice.

[0] https://www.renehersecycles.com/myth-12-disc-brakes-work-bet...

While I don't dispute this, and I have both kinds of bikes, when I talk to "casual" cyclists who have tried disc brakes, they almost unanimously describe the difference as being like night and day. Perhaps the issue is that they are comparing new disc brakes on good bikes, to old crappy neglected rim brakes on cheap bikes. Still, the difference in popularity is unmistakable.

Myself, I'm not getting rid of my rim brake bikes any time soon, but it's interesting to observe how different people experience cycling.

Yeah, I guess component quality matters, the condiditions matter, rider style and goals matter. It seems like there are plenty of reasons to prefer disc brakes (especially hydraulic), but plenty of others to prefer rim brakes, depending on all of these factors.

For pure road bikes rim brakes are ok IMHO only under certain conditions.e.g. no carbon rims and not much dirt and try conditions. These are not the conditions you will find off-road. Also the difference in wet conditions is IMHo still night and day.

Heh, have you ridden on road? I find it at least as dirty as offroad. If anything more grit in the winter, any moisture and everything (bike, shoes, legs, socks, etc).

Roads are far from clean, and if anything the debris is more abrasive than you'll find off road. I'd rather have normal dirt than tire and disc dust you'll find on the road.

I've had top of the line campy brakes, top of the line shimano (dura-ace), and quite a few of the other options.

Do yourself a favor and try out some decent hydraulic brakes. Now only are they pretty amazing, but amazingly consistent. Even in rain, heat, cold, etc. Also it's MUCH rarer to have to undo a brake, just because your wheel went out of true.

Try to track your use, going downhill and hit a puddle, do you drag your brakes? Why? Wait till they grip again? I had no idea I had such habits.

Yup, definitely. Agreed about wet riding. The weirdest one was coming out of my cold garage into a hot humid day, and the water condensing on my rims. That's why I say I wouldn't get rid of the rim brakes, but appreciate why they might be in decline.

I've tried hydraulics on friends bikes, definitely nicer, but again not enough to motivate me to switch.

That's how it is with all of these improvements. Someone will always have newer, slicker gear than me, but I keep riding. ;-)

Heh, rene makes a business out of being different, and has some good ideas, but they do push it to far sometimes.

Sure I get it, a stoppie shows that the brakes are not a bottleneck, it's the traction. So sure, sometimes, on some bikes, with some riders, under some conditions you get perfect braking.

However in the real world there's various rim surfaces (aluminum, steel, carbon fiber), with a variation of water, grit, sand, snow, ice to complicate things. Cable have friction and slack. Rims sometimes are not perfectly round/true in both horizontal and vertical directions. Brake pads are rarely perfectly aligned (the alignment changes as the pads wear), rarely nice soft rubber (they glaze over with heat and/or age), and are rarely braking on perfectly clean rims.

So yes, I've done a stoppie with rim brakes, but the average performance of average hydraulic disc brakes greatly exceeds the average performance of rim brakes. Their other complaint about being grabby is highly brand specific, plenty offer great modulation. Not only to discs brake better, modulate better, and tolerate temp changes better better, but they also tend to apply more even pressure. Even small differences in trueness tend to create spots on the wheel that brake less or brake more.

I didn't realize how big the difference was, or the habits I had with rim brakes. Took me awhile to unlearn dragging my brakes when ever I hit a puddle, waiting for them to catch again.

Sure if you have a pro mechanic realign your pads before every ride you'll rarely run into an issue that rim brakes handle well. However if you spend more time riding than maintenance discs will serve you well.

There's a reason even the road racers, the most conservative of the bicyclist, are switching to discs.

When I was a city rider to commute, pads alignment was a real PITA and the main reason that made me switch to disc brakes. I was always feeling braked and spending more effort than really needed because one pad was touching the rim. With disc brakes that feeling disappeared and never came back, although you still need to do some maintenance from time to time.

Heh, yes, less maintenance, but also less finicky.

Brake pads on rim brakes are a nightmare. They follow a 3-d arc as they approach the rim, which is itself a very complicated 3d surface. Ideally the front edge of the brake pad hits slightly before the rear edge, to avoid squeal... but not too much or it will engage too softly. Even minor wear changes the engagement point. Cables need maintenance, they wear, get kinked, require lubrication, and it's easy to get the tension wrong.

It's all a mess, and even when perfect, and it's dry, not too cool, not to hot, not dusty... they still get worse with every use.

On discs it's more like replace the pads when worn (no adjustments, just remove the pin, pull the old pads, push the cyclinders in, put in the new pads, and put the pin back in). Sure there's occasionally a need for replacing brake fluid and/or bleeding. But generally way less maintenance, and you get like 90% of perfect braking all the time instead of 10-90% depending on temp, wetness, ice, grit, state of tune, etc.

What about cable over fluid disc brakes for a commute bicycle?

Once you've used hydraulics, you never want to go back to cable. They are so much better on all counts that the tiny weight gain pales into insignificance.

I personally think that mountain bikes with slicks make for a great commuting bike. Fast, stable, low maintenance, and shrug off curbs, steps, and potholes. They also tend to be (on average) more upright for better visibility of the road. Also the brakes are available in the up right position, unlike some road bikes. Never know when a car is going to want the piece of road you are on, it's nice to be able to hop onto a curb.

Also MTB's generally accommodate the widest tires, except for fat tire bikes and generally wider tires can be very helpful when commuting for comfort and making things like a random rock or walnut much less exciting when you hit them.

Commuting with rim brakes inevitably destroys the rims, try commuting for 3-5 years then closely inspect your rims, little micro cracks are not uncommon, and will get worse right up until you have a rim failure.

It's also really nice if you do hit something hard enough to knock a wheel out of true, that you still have two working brakes.

Agreed on everything except the road racers. Maybe some want discs but the pros don't. Discs are more likely to rub for them because pro cyclists generate enough power to twist the wheel. If you are trying to gain seconds over a few hours then the sound of rubbing must be torture. Chris Froome spoke out about it recently. Team Ineos just won the Giro and they don't use rim brakes because their sponsor does not oblige them to. It looks like the reason pro racers have discs is because the bike industry makes them. This is so that they can sell new bikes to people who already have a perfectly good one. It makes no sense for pro riders to have disc brakes. Their high end rim brakes are looked after by mechanics, they are lighter, they don't rub, wheel changes are easier and pros don't do a lot of braking anyway.

> and pros don't do a lot of braking anyway.

That's just not true, there's plenty of braking in the mountain stages. I sincerely doubt that going 90-100Km/h into a hairpin is easier with rim brakes.

Ineos had two accidents this season on descents, first with Moscon in the Giro and then with Thomas in Criterium du Dauphine and even if they might have been just flukes, I'm sure the team is asking themselves questions.

This is something that I think a lot of people at overlooking even they reference pro racing: they ride the bikes their sponsors make them ride. And the sponsors have incentives that are not strictly limited to winning.

The industry can sell MTBs and gravel bikes where disc brakes have benefits. And now e-bikes, that's a huge market.

While in absolute terms rim brakes are probably just as good as disc brakes. The difference lies in the feeling and modulation of the forces.

Also, the disc is a consumable on both types. I have worn down rims to the point where I was scared to use the wheels.

The initial setup can be a bit annoying with hydro discs, but it's a tradeoff I'm happy with.

Cable-pull disc brakes are still a huge improvement over rim brakes in the ways that matter, especially in the wet.

Depends. Many make pretty ugly compromises. Poor pads, not much leverage, and even being single sided which often drags and requires the disc to bend for good braking.

So cable-pull disc vs rim brakes is less clear, more susceptible to case by case differences.

However hydraulic discs are always (AFAIK), double sided, and almost always better than even the highest end rim brakes.

Not to mention who wants to destroy their nice rims by dragging brakes on them, leading to relatively short lives as the rim walls get ever thinner, right up till they start cracking. I'd rather replace a disc than a rim after 5-10k miles.

Rim brakes cannot fit around a wide tyre. Mechanical disc brakes with good pads (this is key, swap them out if necessary) are much more powerful than road rim brakes.

Yeah, my gravel bike was $1000 new three years ago, and comes with "Spyre 2.0" cable disc brakes. Hydraulic brakes feel 1000% better, but I'd still rather have disc than rim. And mine are double caliper.

One thing I love about my brakes is having a second set of brake levers inline on the top of the bar - I believe the Shimano GX (gravel) series has that now for hydraulic. If I ever have to buy another gravel bike, it will have this feature.

Dont tell my wife. She’ll want me to sell 3-4 of my bikes! ;)

Rumor has it that a very prominent British Tour de France competitor rides a re-badged/stealth gravel bike because he finds it more comfortable.

Who is that rider?

I'm a bit hesitant to believe this. Can we have some more details?

Gravel bikes are easy to distinguish from race bikes, even when rebadged. If it was true, many fans and commentators would have noticed already.

Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires. Of course sawtooth vs slick makes a difference in friction. The hubs in the wheels could make a difference too. I use the 28 mm wheels when I go on asphalt roads in the mountains because I don't want the extra weight and friction. 42 mm for everything else.

> Anecdotally my gravel bike is faster with 28 mm slick tires than with 42 mm sawtooth tires.

Out of curiosity, do you know this to be true, or believe this to be true? I ask because the perception of speed with skinnier tires is one of the things the article touches on.

I felt similarly when I put GP5000 28mm slicks on the gravel bike, but when I looked at my ride history, I couldn’t really back that feeling of speed up with actual data, and evidence shows that at least in my case, there was no major difference between 28mm and 38mm.

(Not saying this is the case for you, but I’m just curious).

My experience is the same as yours.

When I rode the same regular routes on my gravel bike on slick 38s vs my road bike on slick 25s (up from 23s, as big as I could fit!), the road bike felt faster but GPS data didn't really back it up over the course of a whole ride.

The road bike is a bit more nimble with twitchier handling sure, but the more jarring ride of the skinny tires gives the illusion of speed. But in the real, non-racing world the data tells a different story. At the limit I have no doubt the road bike is ultimately faster, but that's not most of my riding.

I'm not a racer but am an avid and reasonably fit recreational rider, so I ditched the road bike entirely and enjoy my more comfortable and practical gravel bike, with minimal speed penalty. Plus I can ride on dirt roads and broken pavement with ease and comfort, to boot.

I think most riders are better served by gravel/endurance bikes than pure road bikes.

You also want to measure the amount of power you're inputting.

Could be the same speed, but you need to peddle harder to maintain it

You're definitely faster with the GP5000s and it's not just an illusion. The GP5000 is an extremely fast tire - some of the lowest rolling resistance out there as measured scientifically [1]. Even the fastest 38mm tires are probably going to cost you minimum 10 watts per tire over the GP5000; perhaps even double that.

[1] https://www.bicyclerollingresistance.com/road-bike-reviews/c...

They test AFAIK under ideal smooth road conditions asconfirmed by the picture. On bumpy roads the 10 watts advantage might quickly disappear

10 watts per tire is an absolutely enormous amount given that the rolling resistance of the tire itself is only 10 watts in total. The BRR test also claims that "the drum is covered with diamond plate to simulate an average road" - it isn't completely smooth [1]. If you're riding on roads that are so bumpy that you really need super low pressures (e.g. significantly lower than the 60psi you can run on a 28mm GP5000) then rolling resistance isn't a high priority. But honestly very few actual roads are that bad.

[1] https://www.bicyclerollingresistance.com/the-test

I don't usually do the same routes with gravel and road tires so it's difficult to have hard data to back my claim. The only one I have is 1h 59m vs 1h 56m on a flat fully paved route. So not a big improvement, 2.5%?

However the bike feels lighter with road tires. At low speed I accelerate faster and I can keep a higher speed for a longer time. The 42 mm tires have a shallow sawtooth tread so they can't be as fast as the slick 28 mm ones.

And the bike is really lighter with road tires. One 42 mm tire is 600 grams, plus a larger tube. I don't remember the weight of the 28 mm tire, but it's less and the tube is smaller.

Another big difference is simply the quality of the tire. A supple 48mm knobby could be faster than a stiff slick (and we know the width doesn't matter). The Rene Herse Oracle Ridge knobbies are 48mm, quite supple and corner well on the road, plus they are noise cancelling!

Width matters for air resistance. I can hear the air coming off my 2.1 inch tyres. Rene Herse knob bikes are still pretty loud in my experience!

Yeah, in the mid 40mm range I don't think the air resistance matters, but up above 50, you're starting to make tradeoffs.

TFA: "suspension losses"

Who the hell uses suspension on a road bike, or are they talking about something else?

They are talking about vibrations in the wheels, not a big ol suspension fork like on a mountain bike.

In many ways, modern gravel bikes are a comeback of the "sport touring" road bikes that were popular from roughly the mid 70s to the mid 90s, then became mostly absent from market. Compared with "racing" bikes, they had wider tires, a more relaxed geometry, and various conveniences such as mounting points for fenders and racks. Thus, they were a much better option for the majority of riders who did not participate in serious road racing.

Then for 20 years you couldn't really get a road bike with tires larger than 23 mm, which is totally illogical in places with less than perfect roads such as here in Canada.

Really happy that gravel bikes have brought back some sensibility to the sport, and that they provide a nice "all around" option in a market where manufacturers had been using "super specialization" of products to entice customers to buy more products.

Now I'm waiting for a similar trend to take over XC skiing!

Surly made a couple bike you could put fat tires on - their touring bike and a cyclocross bike. I don’t know if they’re still available but they were selling them in the mid-2000s

Every Surly bike takes wide tires. Their Pugsley was the first mass-produced fat bike, starting back in 2005.

Definitely still available. That segment of the industry has exploded. Another great manufacturer for touring/adventure bikes is Bombtrack.

Many touring/adventure bikes will double as way better commuter than a road bike I feel. They are set up for comfort, long hours in the saddle, and usually have with luggage mounts.

I haven't had to pay attention to that market because my 2007 Surly is still going strong :)

My 15 year old Surly Crosscheck is probably my most ridden bike - it was one of the 'first' gravel bikes (they've been making them for 20 years) before they really became a thing. The cantilever brakes are rubbish but that just makes it more fun.

I have a bike with cantilevers too, I admire their robustness but yep, definitely not the quickest way to stop in a hurry.

If you haven't, and have the budget to do so, try a set of Paul Components mini motos. Fantastic brakes.

Fatties Fit Fine on most of their bikes.

I ride 40mm tires on my Long Haul Trucker.

In my neck of Europe those bikes reached peak popularity in the 90's and early 00's. We called them "city mountain bikes".

Their distinguishing feature was that a "mountain bike" comes with gears (normal bikes don't), which was very popular. The city edition came with fenders, luggage racks, a nice bell, stand, etc.

Big fat tyres, comfy geometry. The tires usually had a slick strip in the middle and grooves on the sides so you had slicks running on pavement and got massive grip turning on gravel.

As it got cheaper, they even started having front suspension.

Looked kinda like this:

https://www.bolha.com/image-bigger/gorska-kolesa/mosko-gorsk...

https://www.velo.si/modules/uploader/uploads/s_product/pics_...

https://www.bolha.com/image-w920x690/mestna-kolesa/mestno-in...

These aren't the types of bikes meant by the one you're replying to, I think: these are basically mountain bikes with modifications for day to day road use. The other are gravel bikes (which is what I assume means the ones used in cyclocross i.e. a sturdier version of a road bike) modified for day to day road use. But yes these citybikes were very popular in Europe.

Touring bike is my favourite. https://en.wikipedia.org/wiki/Touring_bicycle#/media/File:Lo...

Very similar to cycle cross (a wide range of gears) https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Fo...

The hybrid has straight handlebars https://upload.wikimedia.org/wikipedia/commons/thumb/2/22/AE...

Mountain bikes, gravel bikes, are slow. Gearing is for climbing a mountain. https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/No...

Mountain bikes, gravel bikes, are slow

Given the huge difference between the 2 I'm not sure what you mean? Also because these days 'mountain bike' is an umbrella term, whereas gravel bike is still rather specific. E.g. that last link shows already a rather specific segment of maountain bikes: dual suspension, quite a lot of travel on the front suspension, totally suited for going down the hill fast as well.

Yeah the bottom one is close to being a Bomber.

Indeed, for anyone curious, have a look at the 1985 Raleigh (a notable UK company at the time) catalog, and compare the "Road Sport" category with "Sport Touring": https://www.sheldonbrown.com/retroraleighs/catalogs/1985/ind...

Amusingly, here in the Midwest we refer to the skis that we use for poor snow conditions, where there's a lot of mud and muck, as "gravel skis."

The annoying thing is that the industry still tweaks those perfectly functional gravel bikes for "performance" cycling adding useless features like an aggresive low stack geometry, 1x only drivetrain compatibility, nonsense suspension. Jan Heine gave us some of the best advice through Bicycle Quaterly, his books and the Rene Herse website.

The 1-by drivetrain is something I sought out when looking for my Wife's bike ( or last new bike purchase several years ago ). The advances in the range you can stack in a single cassette totally outweigh the upside of a second ring up front. She has no plans to take that bike up HWY 80 to the Blue Ridge Parkway, and apart from that, she gets by just fine even pulling a kid trailer around town.

My experience with 1-by drive is that the simplicity and (hopefully) fewer opportunities for derailment are totally worth it.

One by drivetrains certainly have their advantages, but many new gravel bikes sacrifice 2x drivetrain compatibility for ultra short chainstays and only accept 1x. Notable examples are Marin Headlands and the Gestalt X10 and X11. Others models that also accept 2x have their whole lineup equipped with 1x. If you also want to use the bike as a road bike, good luck with that. It's either climb hills or go fast with current gravel 1x drivetrains, depending on the size of your chainring. For me the new GRX gravel drivetrain from Shimano has been a godsend: a no nonsense subcompact 46/30 crank and a deraileur usable with up to 11-34(36) casettes or a 1x option usable with up to 11-42(46) casettes. If it wasn't for the gravel/all road bike I would have probably never gotten a proper road bike with skinny tires because it's only usable on roads that one shares with other motorized vehicles.

My first gravel bike came with 42t crank and 11-42 cassette. It's perfect for everyday use. You spin out at like 45km/h (or even higher if you can do high cadence) while the 1-1 gear allows you to climb pretty steep hills. Sure, it's not enough for a road race and I prefer 2x drivetrain these days as I do a lot of distance on pavement but I still think 1x is just a better option for most recreational cyclists.

I can't really climb steep hills with 28 gear inches on the road, let alone on singletrack. But yes, your gear ratio is suitable for road.

My all-road bike has 23 (30/34·26.5", 650bx45 wheels). I don't race.

Amen, 50mm on my Diverge.

Is that different from a "hybrid" bike?

Gravel bikes are more sporty. They come with drop bars and geometry to complement that riding position, and will weigh much less than an upright hybrid.

You’ll also find gears to accommodate more speeds and inclines, typically a single chainring with an 11 speed lightweight derailleur vs 3 to 9 speed heavyweight (but clean and easy maintenance) hub gears.

It isn't.

Gravel bike is just a new marketing term.

The geo is actually quite a bit more relaxed than your typical racing bike, which is why I like gravel grinders (at 6'5" and 40+ years old). It's definitely a nicer ride than your typical road tire but not sure I'd go as far as comfy/soft...

The second most annoying thing to me about cyclists are the number of them who complain about the quality of the road or path while riding what is more or less a race bike.

Shockingly, road race vehicles of any variety generally are not built for comfort or ability to handle less than ideal conditions. Stop acting like you think you're in the TdF and get a bike that makes sense for where you ride.

Ah yes I am a cyclist and I approve this message. Reminds me of this saying from an Indian monk:

Where would I find enough leather To cover the entire surface of the earth? But with leather soles beneath my feet,It’s as if the whole world has been covered.

Just replace leather soles with sufficiently wide rubber tires

Thanks for the very sensible quote.

If the quality of the road is bad, gravel bikes are equally as uncomfortable as race bikes. Not talking about non-asphalted roads as race bikes are of course not made for those.

The fatter tyres do cushion it a bit. And most "cycle to work" bikes I've seen (especially ebikes) will have a small front shock

I'm not talking about comfort, I'm talking about ability to handle the surface properly. Skinny nonsense race bike tires get swallowed up by cracks in the road that reasonable tires just go right over. They're more fragile to debris and simply have less traction on less than ideal surfaces because there's just less tread to work with.

That said the idea that more air cushion space doesn't lead to greater comfort is absurd. A tire that has room to compress doesn't bottom out.

It's OK to complain about the quality of the road or path if you pay for it. Heavy vehicles are what make the surface bad and fat tyres or not, riding on a smooth surface is way more enjoyable.

Bad as in not-smooth or bad as in pot holes? I hope not the latter, because that's dangerous no matter the type of bike, and I haven't heard/read many people complain about the former.

Bad as in not smooth, like far from perfect but also nothing I had ever thought twice about while riding a couple hundred dollar retail store mountain bike. Average Ohio roads, not the worst but definitely weathered.

My former housemate had some kind of race bike with a carbon fiber frame, it weighed next to nothing but he was constantly in fear of road debris, couldn't hop curbs, etc. It was a terrible choice for where he was actually riding.

The geometry of gravel bikes is much closer to 90s cross country mountain bikes than modern road bikes.

That's not really true. Gravel bikes have geometries ranging from aero race bike geometriea to hardtail MTBs. I'd say most have very similar geometries to endurance road bikes though (similar stack/reach, 71ish HT angle, 425-430mm chainstays)

In this part of the world they are called "hybrid" bikes[1]. Fast and sleek enough for regular city commute and rugged enough for occasional off-road cycling.

[1] https://www.youtube.com/watch?v=SfLwm_SOzaI

hybrid bikes are a bit different from gravel bikes. the latter tend to have drop bars, more mountain bike-ish gearing and a more road bike like sitting position compare: kona dew (a pretty traditional hybrid) https://www.konaworld.com/dew.cfm kona rove (firmly in the gravel/ adventure category) https://www.konaworld.com/rove_dl.cfm

I'm very happy with this trend, too.

I've always had full-on road-bikes (skinny tyres, etc). While those are great for a ride out on the hills around my parents' house, I now live in the city where the roads are in a pretty bad shape, and more importantly they're very often paved with cobblestones (probably the very same ones laid down by the Romans).

I'm looking to buy an electric bike for my commute, and most bikes have the "upright" geometry. Maybe it's because of my habits, but I don't feel as safe on those, I find them less manoeuvrable and less efficient if I need to pedal hard (though with the electric motor that last point might be less important).

I'm happy those new "all-track" as they're called here exist, with disk brakes and all the creature comforts of regular "city bikes" but with a more familiar-to-me riding position. I'm less happy with those bikes always having a suspended fork, which I've always seen as useless for road bikes, but oh well...

This, plus my group and solo rides are now mostly on forest paths, single track and dirt paths, away from traffic and cars and the stress that brings. The riding is slower but more enjoyable and technical than road riding for me. It seems to wear me out quicker though, I think because of so much vibration and stabilizing of the bike.

Ditching my hardtail mtb for a gravel bike was life changing. I was mostly riding gravel paths anyway, combining roads and gravel my range increased a lot, and commutes are much more fun. In retrospect, it could be that the 4x more expensive gravel bike just is a better bike :)

I use to live in Boulder CO and I would see a lot of people riding the fat tire bikes because they go over poor roads easy. Even see a bunch of people use them in the winter.

I think folks might be interested to consider some of the other myths and tests in the series, such as:

* Titanium is ligther than steel

* Fenders slow you down

* Stiffer frames are faster

* Disc brakes work better than rim brakes

* Higher tire pressure is faster

* Bigger wheels roll faster

https://www.renehersecycles.com/category/myths-in-cycling/

For more nuanced tire testing and results, check out these two more recent articles

* https://www.renehersecycles.com/how-we-test-tires/

* https://www.renehersecycles.com/bq-tire-test-results/

These are interesting articles, but in https://www.renehersecycles.com/myth-12-disc-brakes-work-bet..., it just says outright "Many rim brakes for wide tires are too weak to do this quickly, so in the rain, you end up with almost no braking power at all." It's not a myth, it's just conditionally true.

> It's not a myth, it's just conditionally true.

Sounds to me like it’s generally true, and conditionally not: in good condition with thin tires on a metal wheel good rim brakes can be better than disc.

Je general case is thus that you’re better off with disc as default.

We have a pretty wide collection of bikes, and all of them are in tiptop shape. None of the bikes with rim brakes have the same kind of stopping power as the disc versions. They don't even come close. Maybe there is an ideal bike somewhere that can outperform any of the disk brake systems that we have but if it exists I haven't seen it. Ever. Of course this is still 'anecdata' but I've seen a lot of bikes.

The people that still seem to push for rimbrakes here in Europe are typically semi-pro or pro cyclists, who may or may not have valid concerns regarding injury due to the disc edges being too sharp (they are now usually chamfered to allay this).

The difference is the modulation, especially with hydro discs.

Rim brakes are like drum brakes on cars, they are more binary with not enough braking power that then snap transitions to locking up.

hydro disc brakes let you brake hard and avoid lockups.

> None of the bikes with rim brakes have the same kind of stopping power as the disc versions.

Yes I expect the people who say that rim brakes are better don’t mean "have better stopping powder" as that seems unlikely, but rather "have sufficient stopping power while being lighter / more flexible / …".

I haven't had issues with any of my disc brakes overheating, but that sounds like one reason to prefer rim brakes, rim brakes cool better. That's not an issue for a lot of situations, though.

You should also keep in mind that the articles are slightly dated, so technical improvements may have changed the equation. For example in the comments thread for the disc brake article, people mention that they cannot find disc rotors with sufficient size for tandems. With the rise of cargo and electric bikes, disc brakes with pretty massive stopping power have come to market. Mine can safely stop the bike, me, plus 100kg of extra load for a total of about 250kg [1], the R+M Load Cargo has an S-Pedelec version with a powered top speed of 45km/h. Those brakes will work for any tandem as well.

[1] yes, I tried.

On tandems the problem hasn't been stopping power for years (every since we had hydraulic brakes this has been a solved problem). The bigger issue on a tandem is that when you're going downhill you will end up overheating your brake, whatever kind of system you are using. There is just too much kinetic energy to get rid of as heat for your normal brake system to be able to deal with.

The kinetic energy depends on weight and speed. Cargo bikes easily come into that range, especially the fast 45km/h electric ones. Energy dissipation depends on the size of the rotor and sizes have been increasing substantially. When I bought mine, the standard disk size was 160mm, I opted for the upgrade to 180mm. The current generation of Riese-Müller Load uses dedicated cargo bike brakes with thicker rotors (2.3mm instead of 1.8) and a 223mm diameter on the rear wheel, 160mm on the front. Those brakes have substantially more staying power before they fade.

Edit: Generally, developments for cargo bikes seem to help tandems and tandem developments benefit cargo bikes. There's now an option to use the tandem version of the Rohloff internal geared hub for RM cargo bikes. That's a serious upgrade to all previous internal hubs, especially since you can combine it with a belt drive. It's a tiny bit expensive, though...

Yes, that Rohloff stuff is nice, and indeed a tiny bit expensive.

With proper technique disc brakes wont overheat, especially now heatsinked pads and 203mm rotors are available.

People who overheat brakes typically lack confidence and drag them constantly on descents causing overheating.

I take it you've never been on a tandem going downhill for a long stretch?

That's not a matter of confidence, that's purely a matter of safety.

I've been on a touring bike with a total weight of 130kg down massive hills in Japan

They why would you comment on what it's like to go downhill on a tandem?

I've got a Koga TwintySix, a trekking tandem, fully loaded it gets up to 180-200 Kg (two adults+camping gear, the 200 Kg is the maximum allowed load), the brakes are super good and yet, by the time you reach 70 kph downhill they are no longer capable of stopping the bike, safely or even at all.

A drag brake is a must in a situation like that or your brakes will start fading within minutes during speed reduction (short bursts of braking to reduce your speed to something safe and allow for ample cooling), and long before you really need them.

My comment was around experience of a reasonably heavy bike and braking down steep hills.

Like I said, its about technique, if you are getting up to 70kmh with bad brakes then you have bad technique.

The braking energy dissipated goes up square vs speed, so in that case you brake earlier and keep the speed down.

With that said, I have no doubt a large rotor with out heat soak can easily stop a 200kg bike from 70kmh to zero.

This article doesn't have measurements, or references to measurements. It's just someone's opinions. Cycling already has plenty of those, thanks.

> Disc brakes work better than rim brakes

They really do though. Hydraulic disk breaks have way more stopping power, higher resistance to wet and dirt, don't weaken with each use, and are both lower maintenance in the long and short term, and easier to service and get correct.

It's not out of ignorance the bike uses who need brakes the most 100% use disks (mountain biking).

The argument made is that "rim breaks are disk brakes". This is true in the same sense that topologically humans are donut shaped. It ignores all subtilty. Wheels flex in turns where your disks do not, etc etc forever.

And calipers on disc brakes have a lot more grip on the disc than the rubber brake shoes on rim brakes, which - especially when wet - can be quite useless.

I think the myth is "all disc brakes are always better than all rim brakes". There are definitely reasons it y situations to prefer disc brakes, especially hydraulic, but also reasons to prefer rim brakes.

> but also reasons to prefer rim brakes

Like? I honestly can't think of any. They don't save enough on weight to be worth the hassle for all but the tour de france. They don't improve areo.

Why?

> * Higher tire pressure is faster

For semi-professionals sure this is a myth for normal road surfaces, but for every day use by normal people with no knowledge whatsoever putting just over 2 bar in their wheels since that is what their cars use you definitely win efficiency, al lot.

If I used 32psi in my bicycle tyres I'd be getting pinch flats all the time! I run 35x700c marathon plus', which requires a minimum of 65psi [4 bar] (https://www.schwalbe.com/en/tour-reader/marathon-plus)

Maybe for mountain bike tyres that advice works well.

I use 30psi on my 35mm and 44mm tires on paved and unpaved surfaces all the time. Have you tried, with a good supple tire? Mine have a max of 65psi!

Narrower tires, necessarily inflated to a high pressure, are actually inefficient on a bumpy surface.

A tire's job is to absorb surface defects in the road, and that is not only for comfort, but rolling efficiency.

The extreme example of this occurs off-road. Off-road vehicles benefit from wider tires that are inflated to a lower pressure. If you have an off-road vehicle, it behooves you to take some of the air out of the tires when you go off-road.

25mm road bike tires basically require a polished velodrome; real roads consist of pitted, eroded and cracked asphalt.

If your bike is vibrating from the crappy road, you're probably not going as fast as you could be. Letting some of the air out for a more efficient, smoother ride is risky, if the tires a narrow; you risk snakebite flats and damage to the rim.

For commuting in run-down city with aging infrastructure, you want at at least 38 mm tires. 40 mm is a nice round number. You can vary the pressure for the kinds of roads you're riding on with a lot of margin, and can take it quite low for dirt roads.

I've commuted around town with pressures as low as 45 psi in the back, 35 in the front, in 45 mm tires.

I have story in relation to that. One time I was riding along NW Marine Drive in Vancouver, from UBC down to Spanish Banks. I came down from the hill and then along the flats there were some Spandex-clad road cyclists ahead of me. I pulled up to them and we were neck and neck. There was road work going on up ahead and the pavement had been scraped, leaving it horribly bumpy. I stood on the pedals and just cranked right through it, hardly slowing down. I saw in the mirror mounted on my eyeglasses that road bike guys dropped off as if a sniper had taken them out.

What is the use of narrow tires? It's just fashion, like stiletto heels.

You're commenting on a article that says "we started to question many of the things we had accepted as ‘facts’... we’ll look at some of these myths. We’ll explain why we (and everybody else) used to believe them, and how things really work"

But you aren't qualifying what you're saying: Are you telling us what everybody used to believe? Are you saying you see through what everybody says even without empirical testing? Are you agreeing or disagreeing with the test results presented in the article?

> Are you telling us what everybody used to believe?

No; pretty much everything in my comment is undisputed old hat, so it is kind of tangential.

The main myth is not that any of that is false, but rather than thin tires more than compensate for these effects due to their reduced air drag and weight and so always end up being advantageous anyway.

(And they almost certainly are on a polished indoor velodrome track, where the effect of surface imperfections is next to nonexistent.)

Have you read the article? It provides the analysis and evidence for what you’re saying in a (mostly) rigorous way

> 25mm road bike tires basically require a polished velodrome; real roads consist of pitted, eroded and cracked asphalt.

Most roads in NZ are not even tarmac, they're chipseal. And people were still buying 23mm tires to ride them back in the day.

I felt like a trailblazer back in 2005 or so for getting 25mm :) I was hoping it wouldn't slow me down...

Heh, well thin tires are lighter, accelerate better, and have less rolling friction.

Alas, that's only true on perfect roads. Even normal road texture on asphalt and cement is enough to lose a fair amount of energy causing vibrations (which is after all a cyclic acceleration) in the bike and rider.

I've ridden 125 psi racing tires on a racing bike and noticed that I was noticeably faster (on the speedo) when riding a painted line than on the asphalt. When riding a gentle slope along a river it was quite apparent as I switched back and forth. It was also much quieter. I also trained with my racing team occasionally with my mtb with slicks and clipless pedals, no such difference at 60psi and 1.8" tires.

So it turns out that wider tires allow lower pressures, which are better at absorbing vibrations and allowing most of the energy to return. A compressed tire causes some heat, which some of which is released into the environment, but some also goes back into forward motion as the tire expands again.

So the ideal inflation changes with the roughness of the surface.

A relatively recent development is improvements in material science that allows for wider rims with a smaller weight penalty and lighter tires. Lower pressures also help lower the weight of the tires/rims (less force) and wider tires generally give more protection to the rims, allowing the rims to be lighter. Tubeless also has been a big help, less weight, less internal friction, and more compatible with the wider tires which have higher volumes and lower pressures.

So 10 years ago 50% wider tires/rims had a significant weight penalty, not so much today. So in every biking segment from weight sensitive racing bikes to various flavors of mountain bikes are going wider. A decade ago 1.95-2.1" mtb tires were the most common. Today it's 2.35-2.6", which is a bit deceiving. Tire width for the same performance decreases with diameter. 10 years ago 26" was the most common, today the large majority of decent mountain bikes (say over $1000 for a hard tail or $1500 for a dual suspension) are 27.5" or 29".

So the air in a 27.5" x 2.6" tire is significantly more than the old 26" x 1.95".

Also, humans frankly stink as an engine, and are VERY susceptible to vibration, rpm, temperature, comfort, etc. So unlike a car where comfort isn't directly related to performance, on a bike a happier rider = riding faster and longer. So being 10% more comfortable can lead to real performance gains, and high pressure tires can be very uncomfortable, even to the point of numbness.

So now even road bikes that claim to be the world's most efficient bikes, fastest for a given rider input, are having ever wider tires. People are realizing even at the highest levels of racing a few more mm and a few less PSI can lead to faster race times.

> even to the point of numbness

Even to the point of injury, ganglion cysts are a real risk, especially in wrist joints.

Cheap tires are slower. Reliable tires are slower. It's obvious from the pictures that the fatties they're testing are special, with paper thin skinwalls. I can totally see that a high performance fattie would be just as good as a high performance narrow tire. It's the inelastic deformation of the tire casing (and inner tube) that eats power.

Unfortunately thin-walled high performance tires are also delicate. I've seen people ride tires that can't even survive a couple of kilometers of dirt road.

I’ve ridden their extra lights into some pretty ridiculous places, and commuted on them in a city, and they’re as trouble free as any other tire I’ve had. (In about 7k miles)

I would recommend taking them on technical single track, but they rock for any sort of road riding. They’re certainly fine for the gravel I’ve seen.

(And by trouble free, I mean no flats that I can blame on the tire or some damage to it. I’ve had one slow leaky valve that I had to change on a ride. I’d normally get a flat every 1-2 thousand miles or so with my older tires)

The real test for a city is how many hypodermic needles and smashed bottles can you ride over before being stranded by a puncture in a not-so-nice area of town at night...

This is why I ride gatorskins

Hypodermic needles go straight through gatorskins.

My old narrow tires would tend to collect cuts in the tread, sidewall cuts, and other damage. After a thousand miles or so, I’d tend to be able to see the cords in some of the cuts, and I’d occasionally dig bits of glass or stone out of the rubber.

I just don’t see the same sort of damage after 3500 miles on a pair of 650x42 tires. I’m not generally riding over needles or goat heads, and I avoid broken glass as much as possible.

Yeah, these supple tires are faster but less delicate than you think.

I do think replacing your stock tire with a supple tire at the same width will be a huge upgrade, and wider would just give you a little bit more.

The problem I’ve experienced with these expensive tires (compass, gran bois, etc) isn’t their durability against road debris. It’s that their “supple” sidewalls don’t hold up to the equatorial sun I suffer under. They degrade far faster than the tire rubber degrades. I like riding these tires but they are expensive fast consumables.

Maybe fenders would improve your tire life?

I’ve been commuting on the extra light Rene Herse tires for about a year in the city and haven’t had a flat. They are set up tubeless though. They are a joy to ride and greatly improved the speed, comfort, and handling of the bike. I was hesitant to get them because most of my riding is on city roads with debree, but haven’t regretted them at all.

Which specific tire model are you using?

The Rene Herse tires are just branding on tires he has made for him by Panaracer. They used to be called Compass Tires till he made a deal with the Rene Herse estate to use the Herse name for branding.

He basically asks Panaracer to make everything thinner & lighter and delete flat protection, reduce the tread thickness, etc.. They are fast & potentially comfortable tires for their size due to being made as very racy tires. The Panaracer versions of the tires are still very fast but have a much better reputation for durability, flat protection, compatibility with a wider array of rims, and for being easier to setup tubeless.

I have unfortunately been on rides with people with the Compass/Rene Herse tires where they repeatedly flatted over and over, IMO they are too fragile for me. I have had exceptionally good luck with the Panaracer tires.

This is valuable context.

Yet, some high profile riders such as Ted King (possible the top gravel racer) and Lael Wilcox (ultra endurance racing and bikepacking) use these tires with success. If someone is getting a lot of flats using the Extralight casing, they should consider the Endurance or Ultra Endurance casings and/or setting up tubeless.

But even Jan will recommend the Panaracer Gravelkings when necessary, especially off-road[0].

[0] https://www.renehersecycles.com/how-are-compass-tires-differ...

Those riders are all influencers and likely getting the tires through sponsorship though, that is something that always needs to be kept in mind with cycling. They don't make enough money to necessarily be able to ride what they think is best if something else can be ridden for free or for payment.

These people are routinely winning long distance races on offroad and unpaved surfaces using these tires. That is evidence that the tires are indeed durable, regardless of whether they would prefer other tires.

If that were the case, surely Tour de France riders would use wider tyres to gain more grip going around corners, especially in time-trials or stages with sprint finishes.

Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road?

The one caveat this article doesn't mention is worse handling but they replied in the comments about it. And handling matters way more at higher speeds, plus they commented the extra weight matters more for steep climbs too.

This, and a wider tire also has a larger front surface, resulting in more aerodynamic resistance. As every watt counts in the pro peloton, this is an important factor. For us amateur riders, probably not so much.

I was a little surprised: the weight difference isn't huge. It is about +27% between Conti 5k 25mm and 32mm, or 60 grams per tire.

Aerodynamics are the only real reason, I think.

They're already using wider tyres than a decade ago.

Yes. Much, much wider.

I nearly passed by this comments section because i assumed everyone already knew this was true.

I think you're exaggerating a bit.

From 2018:

https://www.businessinsider.com/tour-de-france-wider-tires-l...

"It depends on the road surface, but 10 years ago the standard was 23mm tires at 8 or 8.5 bar, or 115, 120 psi," Brown said. "And now it's 25mm for regular road racing and 7 to 7.5 bar for front and rear, so a little less than 100 to 110 max on the bikes."

2mm and 10psi less is not that huge a difference.

It's pretty big when you take into account whole context. Stuck up "socks size is a rule" UCI, historical norms, technical limitations (25mm is a limit for caliper brakes), tire tech (wider tires used to be heavy)....

My prediction is 27mm being the norm in next 5 years.

Currently I'm riding a decade-old road bike. It was fancy at the time because it fit 25mm tires without issues. People would give me shit for "slow" tires on group rides. But 25mm tyres improved a lot in that time. Now I wish it could take 27mm :(

25mm is not a limit for caliper brakes? No idea why you claim that. One of my bikes has calipers and can fit 33mm tires.

Also 28mm is extremely common; 27mm doesn't exist.

There are definitely calipers that can't take a 28. And the mounting bolt position isn't a precise norm, there are frames that put the brake considerably closer to the rim than others. And not without reason, the effective length of the caliper arms has an obvious influence in brake leverage.

Classic road bike caliper breaks don't >25mm. 33mm would be cantilever CX brakes. Or a weird type of caliper.

Nit-picking, but 27mm is very common as the "actual width" of tyres branded 25mm.

8% width and 13% pressure is significant.

True. And these days, "wider is faster" is the cycling myth in need of getting corrected. Because is mostly a tie, with a very soft optimum between clearly worse extremes (neither 10 mm nor 10 inch would be fast). And people who feel in the mood for "overthrowing the old" will often do comparisons were they lower pressure on the wider tires, but don't really lower then adequately, they compare a narrow tire at the lowest and of its useable pressure range to a wider tire at the high end of its range and, surprise, with these conditions the wide one rolls easier. The assumed optimum has shifted, but it hasn't run away.

Regardless of whether it is the case or not, Tour de France riders would not use wider tires to gain more grip around corners because ... wider tires do not add more grip.

You get a larger contact patch from a wider tire, but that patch has less pressure.

Grip (static friction) is coefficient of friction, times weight. The coefficient of friction is a constant which depends on the materials. Rubber on road is no exception.

That’s the first order effects, however substances deform under pressure which is just one of many complexities involved. For car tires on dry pavement you get maximum grip from racing slicks. Unfortunately they need to swap in the rain.

First order effects are the only effects which matter in cycling. This isn't aerospace.

Racing slicks are a different material.

In Formula 1 racing, you go through multiple tires in one race.

In consumer driving, tires are expected to last 100,000 km or more.

There is even the practice, in racing, of using chemicals to attack the rubber to soften it.

> In Formula 1 racing, you go through multiple tires in one race.

They could easily make a tyre which lasts the length of a race, but they mandate pit stops and two different tyre compounds to add interest - teams can use the mandatory pit stop to “undercut” or “overcut” competitors.

In fact, IIRC, for the 2005 season, changing tyres mid race for anything other than safety reasons was banned.

> In consumer driving, tires are expected to last 100,000 km or more.

This is much closer to 25,000-50,000km, and peaking at 70,000km. Source: https://www.pirelli.com/global/en-ww/road/how-many-kilometre...

Using a different material is in effect irrelevant, they still get maximum grip from maximizing contact area because of how rough roads are. Ultra narrow tries need higher internal pressures, which limits how much the deform and thus reduces grip.

Also, F1 cars are going up to 246 mph and doing heavy acceleration and breaking throughout the races, which seriously heats up the tires. Normal road tires would actually die sooner under those conditions. Just read up on who long tires last when people are doing street racing, burnouts, etc.

I might be missing something here but I believe slick tire compounds are geared toward longevity at the expense of lower grip. Unless you are referring to racing tires in general which are grippier than their street equivalents.

Racing slicks are a type of flat tire designed for maximizing grip in dry conditions. https://en.wikipedia.org/wiki/Racing_slick

Slick tyres are not suitable for use on common road vehicles, which must be able to operate in all weather conditions. They are used in auto racing where competitors can choose different tyres based on the weather conditions and can often change tyres during a race. Slick tyres provide far more traction than grooved tyres on dry roads, due to their greater contact area but typically have far less traction than grooved tyres under wet conditions. Wet roads severely diminish the traction because of aquaplaning due to water trapped between the tyre contact area and the road surface. Grooved tyres are designed to remove water from the contact area through the grooves, thereby maintaining traction even in wet conditions.

Ah, so that terminology refers to the absence of tread. Thanks for the link.

> The coefficient of friction is a constant which depends on the materials.

This is an approximation. It holds here, but it doesn't hold for (say) figure skates on road.

That is false; you might be thinking of figure skates on ice. Steel on road obeys coefficient of friction.

(I promise I will keep that in mind the next time I attach skates to a bicycle frame.)

Steel on road obeys the coefficient of friction… until it starts cutting into the road. Unless you're very light, that's going to happen if you're going an appreciable speed wearing figure skates and then try to stop.

Yes; anything cuts into anything else if you concentrate enough weight into enough of a small area, or there are other extreme factors involved like things melting.

E.g. A carbide bit milling a stainless steel object is clearly not following carbide-on-stainless coefficient of friction.

Rubber tires does not generate grip through simple static friction. They stick to the road in two different ways, adhesion and deformation. The adhesion is weak molecular forces that stick the rubber to the road like sticky tape, a larger area will have more adhesion. The deformation deforms the tire to follow the surface and dig into it. Because rubber is viscoelastic, the force is greater on the lagging side of a bumb when the tire is slipping.

The adhesion is greatest in the front of the contact patch where there is less slip and a wide tire has a wider but shorter contact patch, so it has more grip from adhesion.

If you keep the pressure in two tires the same, a wider tire will have the same contact patch area as a narrow tire since they will carry the same force and force is pressure multiplied with the area.

From TFA: “ We tested our tires on smooth pavement at 29.5 km/h (18.3 mph), and found no speed difference between narrow and wide tires.”

A professional peloton rides at 28-30mph on the flat and significantly faster towards the end of a flat stage - I bet at higher speeds, for professionals where every percent matters, it does make a difference.

Certainly for my level (and I have ridden for an hour at 18mph average) it doesn’t.

It is worth noting that tires used by the pros have used slightly wide tyres over the years, and for events like Paris-Roubaix and Flanders, they absolutely use wider rubber on frames with more clearance.

"We tested our tires at the same speeds and found no speed difference". You don't say?

The problem is that wide tyres tend to eat lots of momentum in corners.

When going mainly straight and/or on uneven ground, use wide tyres. When cornering a lot, use narrow tyres.

Also, they have higher raw weight, so thinner is better uphill.

This is actually not really true. Competition bikes have a minimum weight nowadays, and technology is that advanced that it wouldn't be a problem to add some weight here or there because the bike would stay the same weight in total as they have so much margin else to keep in track with the minimum weight. This is why most teams have switched to disk brakes btw, and that they can have all the electronics onboard with power meter, bike computer etc.

But there's rolling "sprung" vs. static "unsprung" weight (the examples you listed). You care a lot more about rolling weight as that affects the acceleration characteristics of the wheel - that's really important at the limits.

If you bother to do the math, but simplify things so that all the mass of wheels is at the contact patch, you'll end up that rotating mass has twice the kinetic energy and takes 2x effort to accelerate and decelerate. Now if you check how large fraction of the mass of rider and bike the wheels are and how fast bikes accelerate, it's kind of insignificant.

Technology was advanced to routinely end up with bikes beneath the minimum, but those days are over. With wider tires, disc brakes, excessive focus on aerodynamics and even wider gear ranges they are usually racing considerably above the limit. These days you'll find bikes in the range of 5000 euros advertised that are considerably heavier than what you would have got for 1500 ten years ago.

Static friction being constant regardless of contact surface presumes a uniform surface consistency (uniform frictional coefficient).

Large (an knobby) tyres are a statistical bet that there will be sufficient friction somewhere on the contact patch. When riding over nonuniform surfaces (dust, loose pebbles, twigs, mud, leaves, and embedded rock), that's a gamble the large and contoured tyre is far more likely to win.

On a velodrome deck, not so much, and cross-sectional area, thermal losses from compressive deformation, angular momentum, etc., favour thinner tyres and higher inflation pressures.

Is the static friction what is going on with wheels? Why do race cars (dragster, F1, etc) have wide, smooth (un-knobby) tires if it's so disadvantageous (no gain, but higher weight and moment of inertia)?

For your standard street-car tyres ... mostly, modulo variations in surface, rain, snow, mud, etc. On reasonably fresh dry clean tarmac though, yes.

For racing tyres ... you're getting into a differet set of circumstances and uncomfortably far from my knowledge and experience, though my understanding is that the rubbers are specifically engineered to be sticky, more so at high temperatures (hence why drag racers spin out, it warms the tyres). That's no longer the domain of static friction.

There's also the matter of thermal management, where tyres at high speeds generate a lot of heat. How much size affects and/or is determined by this, I don't know. I am aware that street-tyre speed ratings are based on thermal properties, however.

Knobby tyres are most effective on non-uniform surfaces: dirt/rock and mod most notably.

It is my understanding that race cars have wide tyres to shed more heat. Tyres melting is a problem at F1 speeds.

Softer tires give more grip but are less resistant to shearing forces. Having a wider tire helps with that.

When you're outputting on the order of 350 kiloWatt per wheel you want to have enough contact area not to spin through, the same goes for taking fast corners, where that width translates into grip.

Here's a pretty interesting article discussing Le Tour slowly getting wider and wider tires, compared to a decade ago [1]. Granted their use case is going to be at a very different scale than most rec/serious non-pro riders. But I know that most all my friends and I ride 28s on our road bikes these days compared to 23s a long time ago. More comfort and more forgiving.

My current road bike maxes out at 28, but I'd probably go a little wider if I could due to the nature of the roads around here (lots of potholes, chunks, crappy shoulders, etc...)

[1] https://www.businessinsider.com/tour-de-france-wider-tires-l...

You also have the theoretical perfect tire vs the actual best for the rider - the more comfortable tire may be better overall as it allows the rider to perform better and for longer.

Tour De France riders do use wider tires than they used to these days. At some point the width starts imparting aerodynamic drag penalties that are worse than the handling gains.

You can't really rely on the Tour de France peloton for guidance. They're pretty conservative and, to a degree, ruled by fashion and sponsors.

I guarantee the masters of marginal gains, Sky (now Ineos Grenadiers), will have spent some resources on looking at which tyres are actually faster for them, regardless of fashion or sponsors.

I think it’s safe to say that whatever they ride on are the fastest options - and every other team would follow - or that within a certain set of parameters, it doesn’t matter.

I just tried to search to see if Ineos run different tyres on different race and stages, and found nothing conclusive.

According to eurosport commentary they do change wheels and tires based on the race. That said they use rim brakes so probably never go over 28m tires.

Cycling teams spend tens of millions each year, with Ineos going over € 50m some time ago. Are they conservative? They benchmark their material in wind tunnels. Sometimes they bend the rules with high-tech material[^1]. There's no way a team competing in Tour de France would choose fashion over performance.

[^1]: https://www.theguardian.com/sport/blog/2017/jul/03/vortex-su...

And quite a bit of the money they spend comes from companies trying to sell gear to hobbyists. It's a rather wild mix between ride what makes you fast and ride to pretend that it makes you fast.

Not sure what gear Inoes grenadiers is selling to hobbyists.

Pinarello bikes, Shimano groupsets, Fizik saddles, Kask helmets, Castelli kit, Oakley glasses, and all the other things you see surrounding the fat guy at the coffee shop on a Sunday morning ;)

None of them are the products of Ineos.

All of them, and many more than I managed to think of, are also sponsors of the team¹.

¹ https://en.wikipedia.org/wiki/Ineos_Grenadiers#Sponsorship_a...

"Man, you sure like Tide".

-Mitch Hedberg riding in a racecar

The whole thing is a fashion show with very narrow limits of what the UCI wants people to do. The rules that ban e.g. the famous Lotus bike were explicitly stated as being meant to discourage wind tunnel testing. Fairings and recumbents have been banned for nearly 100 years because they're too much faster than UCI-style bikes.

If you want fairings and recumbents, look up IHPVA. They have been arranging competitions where these are allowed for a long time, with very little popularity. I think the main reason is that time trials where the team with most money wins are boring, and UCI has more or less figured out what limitations make the race interesting.

Now compare the situation with mountain biking. UCI didn't adopt it at first either (IIRC the claimed reason was they already have cyclocross that is almost the same thing), but after it was popular enough they didn't really have a choice.

It's not about fashion, it's about maintaining an enjoyable and popular sport. 4D chess is probably more "interesting" than regular chess, but people play regular chess because it's a good game that people know and understand. They could start allowing funny looking bikes, maybe off-road sections and, heck, why not an army style assault course? But at that point it's just not the Tour de France any more.

> 4D chess is probably more "interesting" than regular chess, but people play regular chess because it's a good game that people know and understand. They could start allowing funny looking bikes, maybe off-road sections and, heck, why not an army style assault course?

That's an absurd comparison - it's not like we're talking about changing the course or the rules, and it's not like the UCI rules have people consistently using historical-style bikes (they rapidly adopted electric shifting, or novel frame materials, for example). In the world of fencing we have both sport fencing (try to win by whatever means within the rules) and historical fencing (trying to match historical materials, styles etc.) and both those are distinct and interesting disciplines. But adding ad-hoc rules to exclude some innovations but not others, as the UCI does, is the worst of both worlds.

You mentioned recumbent bikes. These would massively change the game as drafting wouldn't work any more. Riding in a peloton wasn't always a thing, of course, but it has been in recent years and it works well. The UCI do change the rules, but they are very conservative and that's a good thing, I think.

Drafting still helps for recumbents - less than for an upright since your drag is lower, but it's not like your drag is zero.

The UCI are conservative in some areas, but they're not conservative when it comes to something the big-name manufacturers want to sell (like electric shifting). It feels very artificial to me.

> Doesn’t a greater surface area touching the floor means more frictional effects when pushing against the road?

Good question because at first I thought it might be negligible due to the tire normally being in a state of static friction relative to the road. But some quick searches showed me that rolling resistance is related to how large the contact point is, like you suggest, along with a variety of other factors. https://en.wikipedia.org/wiki/Rolling_resistance

I don’t know how reliable this is, but googling brought me to this site which compares bicycle tire brands according to rolling resistance on their test machine. Apparently, some 25s have all the 23s beat. If true, the variability range for bicycle tires is a lot wider than I expected. https://www.bicyclerollingresistance.com/

I've bought a few tire models after researching at bicyclerollingresistance.com, and while I certainly don't have the means to do proper scientific research, I feel like I did buy the right stuff.

Same. I don't have any rational basis for it, but I've been happy with my tires. I think the best thing I learned from that site is even slightly larger sizes have a much bigger effect on puncture resistance than better construction.

I love brr.com and have used them a lot, but in the context of this thread, it's important to consider that the surface they test the tires against do not have the kind of imperfections you see on the road. This means lower pressure will always perform worse in their tests, which goes against the more recent consensus in that each road has an optimal pressure depending on its roughness.

One thing every person has missed so far is that often the TDF riders are on rather narrow bikes with very little clearance.

This helps give an aerodynamic profile. Even at a few watts, this is considered worth it. You would likely have to do a lot of research to go with bigger wheels, as that would been wider fork, and thus throw off aerodynamics.

A bit daft, in my opinion, given that it's mainly the domestiques who are in the wind and the ones behind, and in the peloton, can be putting out significantly less energy. May even be better for recovery having a bit more comfort on the bike through wider tyres with a bit lower pressure.

Path Less Pedalled recently had a great discussion on this with Josh Poertner, the owner and president of Silca, the tire pump company:

https://www.pathlesspedaled.com/2020/01/09/your-tires-are-ly...

Tour riders are EXTREMELY conservative, well they were back when Lemond pushed clipless pedals, more helmets, and aerobars.

The nameless scapegoat who was totally the only person using EPO pushed more thorough full-system wind tunnel testing/aerodynamics and a lot more scientific testing, and even (gasp) clincher tires.

Euro riders for a long time worshipped Eddy Merckx (who was totally clean and never doped) and thought you basically only needed an italian bike and nothing else and were culturally averse to change.

Also, keep in mind the Tour riders are basically showcasing industry products, and those products aren't really that diverse in their sourcing, especially with globalization. They all run on whatever they are getting for free or at a vast discount from the two or three providers in each equipment category.

> "If that were the case, surely Tour de France riders would..."

Apologies for appearing to pick you out here, but your comment is representative of a number of eminently "logical" comments made here (as well as many analagous comments on HN in general). So, modern professional cycling is a sport with a 100+ year history, and in 2021 represents a bizarre fusion of the sports entertainment industry, the romantisation/revival of the past, celebrity culture, global cycling manufacturers, the mid-life crises of Wonka-esque team owners, the aestheticisation/fetishisation of the working class, the 'Olympics industry', lurking labour disputes, the fast fashion sector, the ad-hoc application of modern sports psychology, a looming confrontation with its historical emphasis on (mostly horrifically underpaid) white males, neoliberal economics, petty and bountiful financial corruption, widespread pharmaceutical corruption, and the influence of petrochemical money from several ex-Soviet states... All mostly filtered through the celluloid lens of France and Italy, two European nations that have an extremely complicated relationship towards their own history which comes out as a muted pageant of lukewarm national pseudopopulism that is not only is confused within its own borders, but is more-or-less unintelligible to those in the Anglosphere. To imply in any way that a kind of efficient market analysis can apply to decisions made within this sport (that has, if I remember correctly, strict rules about sock length), suggests an insufficient engagement with the background.

Can anyone recommend serious science and engineering sources on bicycles? I've looked hard and only found a couple:

* Bicycling Science by David Gordon Wilson: Book by MIT mechanical engineering professor, going back four editions to the 1970s. https://mitpress.mit.edu/books/bicycling-science-fourth-edit...

* "Bicycle Technology" by SS Wilson in Scientific American (Mar 1973): Great starting point on the technology and it's development. PDF: http://veterancycleclublibrary.org.uk/ncl/pics/Bicycle%20Tec...

Here's a few more I haven't yet pursued:

* Journal of Science and Cycling: Open access online journal https://www.jsc-journal.com/

* International Human Powered Vehicle Association (IHPVA) and World Human Powered Vehicle Association (WHPVA): Apparently one association that split acrimoniously in the 2000s. I haven't pursued this.

* Cycle Engineers Institute (CEI) (UK)

* European Cyclists Federation (ECF)

I'd love to find other publications, and a community and forum. When I ask around at bike shops, most people refer me to Park Tools, which isn't what I'm after.

If you're interested in wheels, check out The Bicycle Wheel by Jobst Brandt. If you're building wheels it's a must have.

https://sheldonbrown.com/

I don't have a reference, but I feel it's important to find something as recent as possible. Bike geometries, MTB bike geometries in particular, have changed in the last 10 years. And full suspension became mainstream.

Is the data available somewhere ?

It doesn’t match my experience at all. I have a road bike and a gravel bike - same quality range (gravel slightly higher). At low speeds, that may be true - the difference is negligible. But at higher speeds / power outputs, the road bike beats the gravel hands down - by a significant margin (big enough to be felt, without a power meter)

Does your gravel bike have road slicks? Is your geometry the same, i.e. your reach and drop is the same?

No. Fair point indeed - the tires are not the only difference. I suspect they are one of the biggest though (based on subjective feeling - for what it’s worth).

It's almost physically impossible for the tires to be a bigger difference than geometry (and thus your position), specially at faster speeds as you mentioned, because aerodynamics quickly dominate the overall resistance you're fighting to keep your speed.

My impression from reading articles and technical reports about this is that there's a couple of things going on.

First, I think the wider-tires-are-faster argument has to be appreciated in the context of the narrow-tires-are-faster argument that dominated for a long time. With the latter paradigm, you wanted your tires as narrow as possible, with some lower boundary constraint due to wheel and tire thinness limitations, maybe around 20-21mm. The former paradigm emerged in part in contrast to that, in that "wider" doesn't mean "infinitely wide" but rather "wider than what's typical for people striving for narrower tires". Some of the arguments about rolling surface area are maybe understood in that context -- the patch of tire in contact with the road maintains the same area as a minimal area under the narrow tire paradigm, and then it starts to become larger, at which point you start increasing friction theoretically with more tire surface area in contact.

The other argument for wider tires is about impedance gains due to wider tires -- decreased vibrations basically. This is different than decreased or equal rolling resistance per se. However, there are eventual aero losses for wider tires, as well as weight increases (which then increase rolling resistance). Eventually these aero losses and weight increases overshadow any impedence gains, and the wider tires' costs exceed their benefits.

This is the sort of thing about cycling that is frustrating to me. I love cycling, but so many mechanical factors get really oversimplified: costs aren't often realistically assessed against actual gains, and sometimes gains are very restricted in the circumstances under which they apply. Disc brakes, for example, are safer, but you see little discussion about whether the safety margin they afford actually would make any practical difference in scenarios in which accidents typically occur (e.g., where a car is coming from the side or a blindspot), and they're often heavier and less aero (so yes, they save your carbon wheels, but you almost have to have deep section carbon wheels to make up for their weight and aero costs to begin with). I'm not saying disc brakes are a bad thing, but I think in practice their gains are more complex than is often made out to be. In the same way, wider tires are probably more optimal than a lot of people thought in, say, 1985. But I think the pendulum has swung a bit too indiscriminately in the other direction at the moment. What's probably most accurate is to say you want the widest tire that affords some impedence gains given your typical riding surface, and not anything wider.

Aero effects increase exponentially (?? polynomially?) with speed (that is, as your speed increases, aero effects become more of a factor in further speed increases), which would match your experience. As your speed increases, the wider tires become more and more of a burden, and require higher wattage to compensate for.

All sports with any significant tool involved are full of misperceptions and myths, not supported by science. Cycling is full of them, but it's not the only athletic discipline like that.

This is an old article that compares tires in the 20-25mm range. The bike industry has moved to wider tires and 25 or 28mm tires are now quite common on road bikes, and gravel bikes have much wider tires. I would be the optimum is around 25 or 28 for road bikes on typical roads, especially as aerodynamics become a bigger factor.

They (Jan and the RH crew) have done several versions of this over the years, and the takeaway is that some gravel bikes feel slower due to geometry, rider position, Q factor, and so on, but the tire width isn’t a factor.

(I think one was testing the open vs firefly, with similar riding positions but drastically different wheels)

Don't forget Jan's signature word: planing.

This is prob the Open vs Firefly test you're thinking of: https://www.renehersecycles.com/what-makes-a-bike-fast/

In the test, they apparently isolated the wheel weight by swapping out wheels on the slower-on-paper Firefly and the bike didn't ride up the hill significantly faster.

However Jan Heine's experiments are often pseudo-sciencey and subject to rider effort. In this test, there were no power meters to show the difference in rider efforts between the two bikes. But somehow planing gives you free watts.

Yeah, the lack of power meter data in their tests is really frustrating.

Jan has a PhD in a science (geo I think), and has done bike experiments with Jim Papadapolis. I would generally take his experiments over most random ones cited on the net.

Gospel truth? No. Probably not. Generally pretty good if you look at what he’s actually testing? I think so.

(Disclaimer, Jan was a teammate 25 years ago, and apart from not having talked since then, I’d consider him a friend)

https://www.bicyclerollingresistance.com/ compares some different tires.

Jan Heine's whole claim is that these tests are wrong and his method reveals the truth. It's so frustrating that he doesn't test any mainstream tires so we don't even see how the results match.

Absolutely, Jan isn't the only one running some numbers, nor the most objective / consistent. Here are two sets of better measurements on a range of sizes of a single tire model, on the same wheel, over a range of pressures, with precise measurements of critical factors like tread depth, sidewall thickness, tread thickness, real world actual width, and actual rolling resistance measured in watts:

https://www.bicyclerollingresistance.com/specials/conti-gp40...

https://www.bicyclerollingresistance.com/specials/schwalbe-m...

So, wider tires mean you can run a comfier lower pressure at the same rolling resistance. Looking through the rest of this site, it's also super clear that there are far more significant factors to rolling resistance than width. It's practically criminal this site doesn't get tons of attention!

This article is really a summary, as part of a series on myths in cycling. Here's a pair of much more recent article with more data and methodology and nuance specifically about testing and speed:

https://www.renehersecycles.com/how-we-test-tires/

https://www.renehersecycles.com/bq-tire-test-results/

Years ago I switched from 1" tyres to 2.5" inch ones for my commuter bike and I can confirm that they are not slow at all... as long as you ride in a straight line! As soon as you turn, they suck up all momentum.

The fact that they provide decent straight-line rolling even at 2bar pressure is nice though, especially in a city where cobblestone paving is common. Fat tyres provide some suspension, and a ton of grip.

Still, narrow tyres are the choice for fast riding if you need a bit of agility.

I completely believe you, but the issue is likely not width per se.

Might it be that your tires have a smooth profile down the middle for going in a straight line, but edges that have a more aggressive tread pattern, which engages the road surface when you tilt into a turn?

There are true fat road slicks that have the same smooth profile all over.

I think, tire pressure is also a factor in turning because of the way the tire deforms on the rim. If you have the pressure way down (which you can easily get away with in 2.5 inches), that could be a factor.

A great source of data on bike tires is [0], which has been doing systematic tests on a dedicated test rig for many years and appears to be independent of any tire manufacturer.

After finding this site a few years back, I bought a high-pressure floor pump and Schwalbe Marathon tires for all the commuter bicycles in the family. Haven't seen a flat tire since, even though we have four bikes on the road almost every day.

[0]: https://www.bicyclerollingresistance.com/the-test

They're great tyres for commuting but they're so heavy. When you swap back to regular or race tyres your bike weighs half as much.

Again, I'm not saying they're good tyres, but perhaps best if you have a spare wheelset so you can keep a "fun" set for the weekend.

I love Marathon Supreme tires. They're lighter but I haven't seen a puncture on them; on the other side I experienced breaks in their sides (probably because of clipping a sidewalk or other object) twice.

I usually ride 32mm or 35mm. You can reach a decent pressure and still ride comfortably.

So, I wouldn't expect them to be slower (except in the most extreme cases with aerodynamics), since you can make anything go fast with enough power.

But along that line of thinking, I would expect larger tires to require more energy to keep at speed. A larger tire with a a larger contact patch implies a greater deformation of the tire, which in turn implying greater energy loss.

Cars, using a measurement of gas mileage, have shown this. Smaller contact patches (a condition created with over-inflated tires) result in higher gas mileage, whereas larger contact patches (under-inflated tires) lower gas mileage.

I didn't see this addressed directly, that I saw.

Wouldn't the size of the contact patch be dictated entirely by tire pressure and not tire size? A 100lb person+bike and 100psi inflation means 1 sq inch of contact regardless of tire dimensions.

They're circles on a plane, after all. In ideal conditions they'd only contact at a single point.

No, because the tire has substantial structure and isn't a latex balloon, for lack of a simpler explanation. In the case of automotive tires, the carcass (structure) of the tire governs the contact patch much more than the inflation amount.

So, part of the point of the Rene Hearse tires is that they’re as supple as they can possibly make them. They are producing essentially the same best tire that they can in a huge range of sizes.

(Well, at least until they started doing endurance casing and knobbies, so now it’s more like 4 of the best tires they can, aimed at slightly different target users/races)

Yes, with pneumatic tires the contact patch area is the load force divided by the pressure.

Does it really matter? Unless 1 extra mile per hour will make or break your commute or you're racing, just go with the most comfortable choice.

I've been planning an E-Bike conversion and it looks like wider tires would be a better choice, as would shock absorbers which everyone says are less efficient.

I'll give up that efficiency in a second if it means my ass and legs aren't sore when I get to my destination.

If you’re going a short distance: No, it doesn’t matter.

For a longer ride or a trail ride, the loss from the tires adds up. One extra MPH means a lot when you’re doing a multiple hour ride at an average of 10-15MPH.

Tire pressure influences rolling resistance significantly on larger tires. I’ll some times increase pressure on longer rides or for uphill portions. Lower pressures have more traction, so I’ll let air out for the downhills.

It doesn’t seem like much, but everything adds up as you push into longer and higher effort rides. Non bikers roll their eyes when we talk about saving small amounts of weight, for example, but it makes a difference over time with less weight to throw around. Again, you won’t notice on short rides around town but when you’re spending tens of hours every week on the bike in increments of 1-3 hour rides, it’s worth optimizing these things.

> One extra MPH means a lot when you’re doing a multiple hour ride at an average of 10-15MPH.

Why spend your effort on optimizing your bike performance by 8% if you can instead simply shorten the distance by 8%?

How exactly do you shorten trails, or race courses?

> How exactly do you shorten trails

You do not go all the way in.

Or pick shorter trails.

Or allow more time.

> race courses?

You may do less lapses.

Or pick a different (shorter) race.

Recreational riding is about going places.

You could shorten your distance to zero by not leaving the house at all, but that's missing the point. I like to go places, and the further I can go on the same amount of energy the better.

1) You may "go places" by driving your car (that goes 50mph) closer to your target place. Then use your "unoptimized" bike to reach your target at shorter distance.

2) "shorten your distance to zero" is too extreme, because we need some physical exercise and want some enjoyable experience.

In this article, "slower" clearly means "slower [when putting the same amount of power in]". Or, equivalently, "need less power to get the same speed". Of course any tires are the same speed if you adjust the power input to compensate.

The contact patch is only larger if the pressure is lower, and with a wide tire the contact patch is shorter and wider. Because of that there is less deformation of a wider tire along the rolling direction which is what creates rolling resistance.

There is another article with a newer batch of tire tests here. https://www.renehersecycles.com/bq-tire-test-results/

Basically, they looked at even wider tires 40+mm and they still aren’t any slower.

Makes my day to see this company on HN. Their Barlow Pass tires in tubeless setup have been an excellent addition to my commute bike. Supple, great handling. There's an efficiency lost on a gravel setup vs road bike, but that's mostly the geometry than the tire.

> These suspension losses are mostly absorbed in the rider’s body. Imagine a bean bag that drops on the ground without bouncing back – all the energy is absorbed by friction between the beans. The human body works similarly. Studies by the U.S. Army found that the more discomfort vibrations cause, the more energy is being absorbed. And the amount of energy that a vibrating human body can absorb is significant – the U.S. Army’s study measured up to 2000 Watt!

Huh, that's a lot. About 3 horsepower. I don't know what the test setup for that is like, but I'm glad I wasn't the test subject.

How is this a test if they didn’t measure energy expenditure? Using a human rider feels like a flaw here.

It's a flaw, but also a feature. If the enhanced comfort of a wider tire reduces the perceived extertion, even though the actual power needed increases, it's a net win in my view.

Their test using the rider's watts is energy expenditure

Case on aerodynamics is weak. I realize their analysis might make sense for extreme endurance events, but they don't generalize to road cycling. They did not test at common race speeds for cyclists. It's 5 watt at 30km/h. That might mean 14 or so watts at 50km/h. It doesn't seem like much but that's significant enough in a road race. And then there are sprints that take place at 60-70km/h

ok, so i'm curious how people feel about this, but i believe, for road riding, wider tires actually do make you faster, to a point of diminishing returns around 32c, because of cadence.

when you hit a bump with high PSI / road tires, your wheel bounces, you're momentarily unweighted from the pedals, and that means your cadence is interrupted. anyone who has raced cyclocross knows; there's a LOT of skill involved in applying pedal strokes at just the right times to absorb bumps while also continuing to apply power, and it's way less efficient than just riding clipless on a freshly paved road. every bump "resets" your muscle contraction cycle, and after a bump, you're often not at the right crank position to apply a hard, sharp pedal stroke to try to catch up.

i believe a ton of efficiency is lost through this biomechanical effect on cadence alone, and that's saying nothing of how much energy you lose in the transfer of forward momentum to an upward bounce impulse.

I suffered with this myth for decades. Now, it didn't affect me too much because the narrower tires that I got, also took a lot higher pressure, and I usually inflated them to the max. And as a result of only caring about skinny tires, I neglected tire clearance on my frames.

Then a few years ago I got a bike that could take wider tires, and was good enough quality to really try out for real. Today I'm one more anecdotal data point in support of wider tires. Now, I don't necessarily opt for the lowest possible rolling resistance. Instead, lowering the pressure allows me to ride in greater comfort but without the tires feeling slow.

And of course other things affect rolling resistance too, such as (from what I've read) the suppleness of the sidewalls and other aspects of tire construction. And I'm not prepared to spend $$$$ to find the holy grail of tires.

I’ve ridden 25mm to 32mm tyres on the same bike, in the same season, and my (absolutely amateur, I’m 250lb and did 125 miles at 16mph) experience is that 32mm tyres are no slower, but are significantly more comfortable, and allow me to ride significantly longer with less fatigue.

Does anyone else have any other data points?

I've spent a lot of time with 28mm tires, but I'm absolutely in love with my 38mm GravelKing slicks. I don't really notice much speed difference (if any), and the comfort level makes up for it if there is. I ride for fitness, so I'm happy.

More details in my other comment (I actually ride a gravel bike so I have the extra clearance for big fat tires if I need).

The comfort level you feel is also a form of efficiency that makes you faster. Vibration absorbs energy and saps your momentum.

This is all anecdotal, but a couple of decades ago I was riding road bikes with standard 622 rims shod with 23 mm tires. In the 2000s I shifted to riding road bikes with 584 rims and 42mm tires because they were frankly just more fun for me (lower pressure = greater comfort and better suspension meant better handling on our rough Northwest roads). The outer diameter was about the same, so I didn’t have to do something weird with the geometry of the bikes.

When Jan came out with 55mm super-supple tires on 559 rims (again that would keep the outer diameter the same) I thought what the heck and got Seven Cycles to build me a custom around the new tires. Now that road bikes run disk brakes, you can run multiple rim size on the same frame so I figured I could always go back to 584/42mm if I didn’t like the crazy wide tires. (I was worried enough that I actually got somebody to build me a new set of 584 rims for the new frame.)

I’ve had that bike for about 3 years now and have ridden several thousand miles on it. Only a few tens of those miles have been on the fancy 584 rims with the (equally nice) 42mm tires – the 55mm tires are even more fun than the 42's were for me. If you ride on mixed surfaces, the extra suspension you get from running low pressures (I run around 26 PSI front/32 back) makes a big difference (or at least it does for me) - both in handling and comfort.

Downsides are increased weight (the 55mm tires weigh about 420 g a piece which is impressively light given the amount of material, but still a lot heavier than those old 622/23 mm tires back in the day) and the increased maintenance of running them tubeless (though of course you can run them with tubes-though given that I haven’t had a flat in 3 years and I’m riding on Seattle streets, I’ll put up with having to monitor the sealant levels every month or so).

I suspect that 42mm is already into diminishing returns for road cycling.

I am definitely slower - 4.5mph or so - on my 42mm gravel bike on road than I am on my 32mm road bike.

But my road bike has slick tyres and the gravel bike’s tyres are more knobbly, and I run the gravel bike’s tyres at much lower pressure. (And there is the difference in geometry of each bike, too.)

I’m not even sure you can buy 42mm slick tyres, so a like-for-like comparison is probably very hard.

Slick tires, by which I mean minimal treat pattern, do exist in 42mm or even wider widths.

(Source: I have seen them on bicycles.)

Rene Hearse sells tires from 26 mm to 55 mm all with the same tread and casings.

That’s part of why they can do this test with some level of accuracy.

Yes.

I swapped RH tires onto my road tandem, 26x44 on the front and 26x54 on the back (from schwable 40mms), and the average ride speed I saw went from the 16mph range to the 17mph range, and the first time out on the new tires we increased our fastest average ride ever speed from 17.25 to 18.25 mph.

And, the stoker is happier because the ride is that much better.

Lots of the wattage gains in tests are often only noticeable when the speed approaches 40km/h. Wonder about the effect at pro levels, if 32mm is viable there.

My longest is 300km with 35km/h avg (185 miles, ~22mph) running 25mm. No problems with comfort. Never tested other wheels on this bike. But I do have a gravel in same price range with wider tires. That I can follow easily in a group, but alone my speed is slower for the same wattage. Might be the more upright position though.

This is a misconception, I think, although your experience seems like enough that I'm surprised you'd make it.

The "big" changes that happen as you approach and go beyond 40km/h are due to (aerodynamic) drag coefficient, which has very, very little to do with the width of your tires.

The changes that Heine is talking about are not related to drag coefficient at all.

Worth noting that Heine himself is a legendary ultra-cyclist. He holds the record on the Cannonball (Seattle to Spokane on I-90, 300 miles) in the self-supported category. He would routinely other riders (e.g. me) even though he had to pull off the interstate to restock on fluids and food.

> This is a misconception, I think

My comment was more general, as in that lots of truths and myths about bicycling stems from people talking about different speeds. So stuff like "x doesn't matter" some amateurs say, but that x actually starts to matter when the speed increases. Or the opposite, lots of marketing about how product y saves z watts making us amateurs buy it, but then that test was on a already perfect setup at high speeds we're never gonna reach.

But given most data is pointing to wider being better (or, not less effective but more comfortable) I'm wondering why pros aren't running wider.

CyclingAbout has some great experiments in a similar vein. You can scroll to the experimemts section here:

https://www.cyclingabout.com/article-directory/

He has a great one about aerodynamics which touches on tire aero as well as luggage and clothing aero. Most of the perspective is around bike touring but it's a fantastic resource. He has dozens of guides too and a comprehensive YouTube touring channel. He does all this stuff while perpetually touring for years, so you know it's from real world experience on the bike.

Maybe I'm missing it, but what was their testing methodology?

Tangentially the same is true for mountain bikes to a degree, and for a reason not mentioned in the article: Wider tires (run with lower pressure) cope better with uneven or soft terrain. This can easily be verified by riding different tires on grass, sand or deep gravel. On the other hand, on smooth and hard ground wider MTB tires do indeed have higher resistance. This was experimentally documented by the German "Bike" magazine.

While this article targets road cycling, from my own casual city cycling experience I strongly recommend wide tires. They forgive much more rider errors and slip less in any case. I personally use 60mm (60-622) Schwalbe Big Apple tires on my 17 year old Utopia Velo steel bike. Make sure the wide tire fits the frame, some city/holland type bikes can only fit some 40ish mm tires.

> in theory, wider tires are faster due to their shorter contact patch, which deforms less as they roll

What is meant by "contact patch"? If it means 'portion of tire in contact with the ground': Assuming the tires are the same circumference, I'd expect the front-to-back dimension of the contact area to be the same, and being a wider tire, the side-to-side contact dimension to be larger, creating a larger contact area.

And given equal force on the tires, wouldn't the same force deform a smaller contact area more, not less? What am I misunderstanding?

> Laboratory tests on steel drums eliminate the rider and thus the suspension losses. If you look at hysteretic losses alone, narrow tires run at higher pressures and thus flex less, meaning they absorb less energy.

> We tested on real roads, with a rider on the bike, and found that the increased vibrations of the narrower tires caused energy losses that canceled out the gains from the reduced flex. These suspension losses are mostly absorbed in the rider’s body.

How do hysteretic losses apply here?

And, why does the increased vibration cause energy losses (which I take to mean reduced efficiency of energy used for movement)? If the energy is absorbed by the tire or is transferred via other bicycle components to the rider, what's the difference in energy loss/efficiency?

If you're going OVER imperfections (i.e. high pressure tyres), you lose some energy going 'up'.

If you go THROUGH imperfections (lower pressure) you don't lose so much energy going 'up' as the tyre absorbs rather than bounces you.

Thank you, but maybe I'm being dense:

Tire hits bump, causing energy B to impact tire. The whole bike and rider go 'up' or just the tire goes 'up'. How is the former causing more energy loss? The amount of energy is B either way.

I can see how one is more comfortable, because the tire takes the hit and not me, but I don't grasp the difference in energy.

When the pressure is lower, less energy is deflected upwards. The tyre flexes over the hit.

        _               \________/
   \___/x\___/  versus       x

Less energy is transferred to the 'up' meaning the energy is still going forward. You still have upward motion, but that's less energy taken away from forward motion.

There is no fixed energy B. If the bump only deforms a small part of the tire, that's little energy. If the bump makes the whole rider jump, thats lots of energy.

The bump is basically static.

The human body is not perfectly elastic, as it is made out of meat. When the bike goes up and down, it makes the meat jiggle or flap which dissipates energy in the flesh as heat. So taking the hit at the tire which is much more elastic instead of in the heavily damped rider is more efficient.

Take a look a slow motion video of riders on a rough road, say some Paris-Roubaix footage and you can see this.

Ah, thank you; that makes sense to me. I didn't anticipate a big difference between a tire and a person in that regard. FWIW, from the article:

> Studies by the U.S. Army found that the more discomfort vibrations cause, the more energy is being absorbed. And the amount of energy that a vibrating human body can absorb is significant – the U.S. Army’s study measured up to 2000 Watt!

Let's not imagine how that study was conducted ...

The contact patch is the portion of tire that is touching the road. A wider tire should have a smaller contact patch... Maybe. A wider tire means the force can be spread out more and should deform the tire less. So the front to back dimension will differ.

The contact patch should be a constant area for a given pressure and load.

A wider tire will have a wider, but shorter, contact patch at the same pressure.

I'm a mechanical engineer and I never would have guessed this. Kudos for doing testing to see what's actually true.

> the air inside a wide tire doesn’t add weight

This is true, but it's not weight that matters for acceleration, it's the mass, which that paragraph gets confused about. The air inside does definitely have a little mass.

The difference in mass between wider and narrower tires does have some effect on handling, even if not on acceleration.

Narrow tires also require higher pressure with a less comfortable ride. Bigger riders, Clydesdales, require more pressure. These rock hard tire inflations are then more prone to snake bite flats. As the discussion section in the article points out, wider tires used to be common. I think we're rediscovering why.

Snake bite flats are precisely from low pressure. The term comes from two punctures that come from the rim pinching the tire, which is due to inadequate pressure to absorb an impact.

Rock hard tire inflations are prone to failure from the pressure itself.

I short handed it a bit. My point was that this 'low pressure' for heavier riders is higher than it is for lighter riders. If you don't increase your tire pressure, the same pressure will cause more snake bites for a heavier rider than it would for a lighter rider.

What about aerodynamics? https://www.swissside.com/blogs/news/back-to-the-wind-tunnel

Wider tires are still slower BEYOND A CERTAIN SPEED as drag increases. Furthermore tire rolling resistance test are done on a bumpy surface, and 25 mm tires > 28 mm.

>tire rolling resistance test are done on a bumpy surface

Which ones are? The ones at bicyclerollingresistance.com aren't road-like-bumpy at least, and that's the most commonly cited page I know of for rolling resistance.

wider tires also let you run lower pressures, which puts you more in the comfort zone of being able to convert to tubeless. not every rim/tire combination works with tubeless, but if you are able to pull it off, it's among my personal top 5 list of cycling innovations of the past 30 years.

I'm missing something: How do lower pressures lead to tubeless?

Narrow tyres tubeless is a no-go as the high-psi required to get the tyre seated and shaped can cause blowouts, especially if you get impact such as a pothole.

Going for wider tyres means you naturally can go lower PSI, but if you drop PSI with tubes you risk pinch-flats ('snakebites'), where striking a hard edge causes both edges of the tyre to puncture (like X___X on the cross section, rather than \__x_/ of a normal puncture). If you go wide, you can then drop the pressure more as you don't have a tube to pinch. This gives you the great comfort, the pliability to absorb road imperfection (which improves speed), and less likelihood of puncture.

As an approximate pressure guide:

    # weight in kg. front load probably 0.45 (45%). tyre width in mm
    weight_front = weight * front_wheel_load
    weight_rear = weight * (1 - front_wheel_load)

    psi_front = (338.14 * weight_front / tyre_width ** 1.5785) - 7.1685
    psi_rear = (338.14 * weight_rear / tyre_width ** 1.5785) - 7.1685

This should ballpark you 15% tyre deflection under load, which was a guide from an old bike magazine on a balance of rolling resistance and comfort.

'davisoneee covered it pretty well, but mostly lower pressures mean it's less of a pressure differential that the sealant has to withstand. "Road tubeless" setups exist for narrower tires, but a lot of them have upper pressure limits around 80 psi / 5.4 bar. Running wider tires / lower pressures gives you a bit more margin of error.

Folks want to run tires at lower pressures, but this increases the risk of pinch flats for inner tubes when the rim bottoms out against the ground. Tubeless setups don't have this risk.

Yes, a bit, but you won't want to ever bottom out, with or without tubes. You can snake bite flat tubeless, you can also damage the rim.

Generally you want enough air pressure to have enough air pressure to have a 10-15% deflection in the tire and never bottom out. Thankfully suspensions help with the pinch flat since they basically time average the impacts.

Do they account for weight? This reads like marketing material, not science.

Another one is that clip in pedals make you faster.

Do you have a source? Anecdotally I've found clipless to make my power transfer more efficient. Some quick googling shows this seems to be true:

"Mean power output was higher using clipless pedals ( = 617 watts, SD = 112) than toe-strap ( = 572 watts, SD = 77), and flat ( = 566 watts, SD = 83)." [1]

[1] https://scholars.fhsu.edu/cgi/viewcontent.cgi?article=1118&c...

I was a life long flat pedal rider.

Started working at a bike shop during college and one of the first things roadies told me was they are indeed much more efficient because you can push AND pull on your pedals - generating a lot more power and making the ability to sustain that power a lot easier.

I think this is a myth - you don’t pull on your pedals to make you more efficient, I think it’s the fact you are not continuously having to adjust your feet as you would on flat pedals.

See https://www.bikeradar.com/advice/fitness-and-training/stop-p... for instance.

a better way to say what you might be saying is, "without locking your feet to the pedal, you expend significant energy with lateral muscle movements to keep your feet on the pedals"

One issue I have with that bikeradar article is this quote:

>Undertake your next few leg-speed intervals at the same cadence (such as 105rpm), but aim to remain more firmly planted in the saddle, with your pelvis acting as a foundation for your legs. This will allow you to maintain chain tension through the entire stroke, eliminating the ‘thud’ through the top and bottom of the stroke (the ‘dead zones’) as your chain loses contact with the freehub

Anyone who experiences what the author describes as "the thud" is pedalling so badly that almost anything they do to improve their stroke is going to be huge win. I'm not sure his advice is on point for people who already have reasonable pedalling technique.

I use clip ins now, have for about 5-6 years. I don't think you actually pull up.

you should actively pull up your leg so the down leg is not working extra to lift it, and the pull up muscles are different muscles so your idle down muscles are still getting a rest.

The pulling up of your leg results in easier pedaling overall, and it is relatively as if you are pulling up on the pedal. Should you actually then pull up? You should go for the most natural sustainable pedal motion for you. When I pedal I "visualize" my feet going in circles, not up and down, it helps me on the "over the top" and "across the bottom" parts of the circle. keeps me sinusoidal!

If you never pull up at all and you are pedaling and feeling tired, try pulling enough to remove the dead weight leg from the equation and you'll feel rejuvenated.

Honestly, go try biking by only pulling up. You don't pull up.

Just do one-legged drills for a bit. You definitely pull up when doing this. Transfer the same muscle activation to two legged cycling, and you're pulling up then too.

Honestly, I pull up. I'm not pulling the pedal up, I'm lifting the leg and pulling my foot up, getting it into postion to push again, same as I would do for running.

you should try it, you can feel the relief in the pushing leg.

I'll go try it. Why couldn't you do that in flats?

You do it with flats too. Clipped in feet just makes it so you don't need to worry about where the foot ends up after that. But it's not a huge difference.

Bike more and you will, it's not particularly noticeable while normally biking. But I really notice it on sprints, but it's also noticeable even with smaller increases in effort over cruising.

It's also quite noticeable when you switch to clipless and go for a hard ride, suddenly new muscles will be sore.

In cycling, clipless = clipped in, which is of course confusing - I think the GP is referring to the same thing as you are.

Clipped pedals refer to pedals with toe straps. Clipless are pedals without a strap, but you clip into. And flat are ones you just rest your feet on.

From what I've read, although I can't remember the source, the difference doesn't really matter on flat surfaces, but clipless perform far better on inclines. I believe this has to do with the angle of the stroke relative to gravity causing some efficiency loss without a clip.

My first impulse, given the loads of data to the contrary, was to just hit that down arrow and move on. But that's not fair, so I'll instead throw out: "got a citation for that?"

There's been studies from Bath University, but

https://gearmashers.com/clipless-pedals-vs-flat-pedals-faste...

Here are 2 dudes that did a trial, they produced more watts going up hill in flats, sprints were a big difference though. These were people used to being clipped in, and not using flats.

Where's the studies to the contrary? Nothing I've seen has been more than marginal at best.

I mean, they do, in the sense that they give a stronger and more secure connection to the pedals which lets riders commit more power.

This is relative to casual toe clips or flats. Compared to old school clips + tightly fastened straps with dedicated shoes they aren’t a huge difference performance wise but no one rides those any more because they’re much more dangerous and much less convenient.

Once you're used to flats, this isn't an issue. If you have good pedals and good shoes, your feet don't normally move at all.

I mean, I ride flats on my mtb because the trade off makes sense, but I absolutely wouldn’t do a hard sprint out of the saddle in them like I would on clipless on my road bike.

Compared to cages or straps, you mean?

This is shockingly unintuitive if you mean compared to flats. The theory is that the force you use pulling up will always have a reduction in the force you use pushing down?

Compared to flats! I also couldn't believe it at first. I'm not sure the theory of it, but I've done long rides with people in both (80+km) and there was no difference in speed. I also would do a 16km route as fast as I could, and there was no discernible difference in avg speed or time.

Huh. I had never heard anyone say that, per se.

For my part, I like clipless pedals because they ensure that my feet are positioned optimally, which reduces fatigue and strain on my joints. Which, in turn, probably does mean I can maintain a faster pace for longer, but it's not like I've ever timed myself.

Back when I was mountain biking, I also liked them for better control over the bike, and easier mount/dismount than toe clips.

I also like them for feet placement. They just aren't faster from my experience. It was not something I expected.

You can pull up and push down. Also if you get a pro fitting then the position of your foot will be optimised to get the max power through the pedal.

Anecdotally they’re faster.

Foot placing definitely, I love clipped in shoes for that. You don't pull though. I can ride equally as fast on flats, as I can clipped in. I've gone on 80km bike rides with people who are clipped in while I'm using flats, and it's the same. Clipped in is more comfortable, in my experience, it's not faster.

I’ve done many 100 mile+ sportives and have done both pushing down and pulling up.

You've done it just pulling up?

Both, pushing-and-pulling for rapid acceleration; as well as just pulling, often going up a hill to give the pushing muscles a rest.

Pushing and pulling at the same time takes a bit of time to get used to, but it can become quite natural after a while.

No data other than anecdotal but totally agree. I use flats on my road bike and look like an idiot but I go just as fast. I prefer to be able to wear normal shoes so I have less to carry. The whole "you can push while you pull" thing makes no sense, my quads are way more powerful than my hamstrings and you never need that much force when pedalling anyway, cardio fitness is always the limiting factor for me, not leg strength/power.

"You can push while you pull" never made much sense to me on the road. Because, you're right, those muscles aren't as efficient, so you're just going to have to pay the expenditure back with interest.

But, off-road, it can occasionally be useful to give 'er one or two extra firm strokes to help power over a small rise or whatever.

Off road the trade-off for me has always been "how quickly can I bail when things go wrong?". With spiky flats and sticky shoes I don't really have any problems with making enough power.

The answer is "twist your heel outward". It's not really any more complicated than lifting your foot from the pedal. The direction is different, but this is why you practice unclipping for a while before going off road.

An opinion piece on the matter of being clipped in vs street shoes: https://www.rivbike.com/pages/the-shoes-ruse

the so-called "half toe clip" is the way to go. I wish I could find pedals that were clipless on one side and would let me install the half toe clip on the other (need the screw holes which usually hold the orange reflectors)

for regular street shoe convenience, they are amazing and much easier to get out of than straps.

I prefer asymmetric pedal sides. I have a pair on my gravel bike that have crank bros. clips on one side, and are flat on the other. Best of both worlds!

Wider tires are not slower. They are heavier. Heavier tires are slower than light tires because they take significantly more energy to get them up to speed.

In particular their inertia is higher, and the tire is the worst place to put heavy things physically speaking.

Not disagreeing with you at all - it is true.

But for most people, whether or not you went to the toilet before starting your ride, or had that bit of cake at the cafe stop, has a bigger impact than the additional grams on the tyres.

Yes, but the effect is rather small, because the rotating mass is small compared to the combined mass of bike and rider.

Also, a typical trick is to go to a smaller diameter wheel and a larger tire, so that the handling and moment of inertia are similar.

For example, I’ve got two rim brake wheels, one 700c 16 spoke aero front wheel with a 23mm tire on it, and one 26” 36 spoke tandem/mtb front wheel with a 44mm tire, and the difference in weight is 200g. (1200 vs 1400)

Even on the road bike, that’s only a 0.4% difference. (Not that they’re compatible wheels, it’s just the only decent comparison I have on hand)

This is not the conclusion the article reaches.

It's not about drag or friction, it's about weight. Wider tires are heavier. Which is a big no no in professional cycling where every milligram counts.

The article mentions this, and concludes that the weight doesn't matter as much as people seem to believe:

> Wider tires are a little heavier than narrow ones. The difference is smaller than many cyclists imagine – the air inside a wide tire doesn’t add weight – but a wide tire has a little more rubber and casing. Won’t this make the wider tires harder to accelerate? The answer is “No.”

> The reason is simple: Bicycles don’t accelerate very quickly. Even a professional bike racer’s power-to-weight ratio is far less than that of the slowest economy cars, and those don’t exactly push you back in the seat when you floor the throttle. Bikes don’t accelerate fast enough for small changes in wheel weight to make a difference.

> That is why professional sprinters can use relatively large wheels (which inherently are heavier) and still win races. The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.)

Ah when I mentioned professional cycling I actually was specifically thinking about mountain climbing. I don't follow cycling much except the Tour. The article didn't mention anything about the climbers, they only mention flat road physics.

Actually due to the UCI imposing a minimum weight, they have a fair bit of weight to play with. It's possible to make a bike significantly lighter than the minimum, so they could, for example, choose to make the frame super light to compensate for the weight of the tyres.

I don't believe it. When I had a cheapo mountain bike, I could hear the tires on the road, especially at higher speeds. With my current road bike, the tires are a lot quieter. That noise translates into lost energy, including lost energy that can't be heard. Sure the bikes differ a lot, but the difference in rolling resistance is stark to me. The road bike also can roll for a lot longer a distance.

It sounds like you haven't read even a paragraph or two. They're talking about road slicks vs road slicks, not mtb tires vs road tires.

I read it. But I didn't think there would be a difference between knobby and non-knobby tires compared to the changing width.

Mountain bike has knobbly tread. This article is taking about wide smooth tires.

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