MIT Aluminum Bicycle Project 1974 (2016) | Hacker News Reader

MIT Aluminum Bicycle Project 1974 (2016)

sheldonbrown.com

195 pointsanschwa149 comments

> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude.

There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stiffer than 6061 aluminum, and the kicker is that this is generally true only if they're extruded. If they're not extruded, the laminate-like grain structure doesn't form properly.

Could make excellent bike frames.

Magnesium corrosion would still be a problem, though. I got some LPSO-Mg samples from Fuji Light Metals, in Japan, and they were quite badly degraded within weeks.

There was a magnesium bike frame back in the '90s, made by Kirk:

https://www.elmycycles.co.uk/m21b0s365p4804/1992-Kirk-Revolu...

https://www.bikeforums.net/classic-vintage/1279777-kirk-prec...

https://www.independent.co.uk/news/uk/magnesium-in-frame-to-...

https://www.flickr.com/photos/11521783@N05/albums/7215764801...

A friend had one. It cracked.

> It cracked.

> "Kirk Revolution cast magnesium"

Cast magnesium is really weak/brittle compared to forgings and extrusions. Its use was not a great design decision on Kirk's part. I suppose they could have wrapped the casting in carbon fiber or something like that, to give it extra bending strength and spread out loads that might cause fractures, but then it would get expensive.

Carbon would cause galvinic corrosion in contact with magnesium, and would also visually hide dangerous cracks- I don’t think a carbon wrapped magnesium bicycle would be safe.

I was just spitballing, but it's possible:

First you coat or anodize the magnesium, which I imagine needs to be done in any case. Then you apply a layer of epoxy. Then you wrap in carbon/epoxy. Done properly, there's no direct contact between carbon and magnesium, and you're probably less likely to see corrosion in the Mg-CF composite than you are with magnesium by itself.

The epoxy barrier might work, but in general encapsulated metals are risky because they are impossible to inspect for corrosion and cracking so fail without warning, and the encapsulation can block surface oxide formation which causes crevice corrosion- especially if small amounts of salt and water get in there, which they will over time, even in epoxy.

I’m sure what you are saying could be done- especially to basically add stiffness to key regions of a carbon racing bicycle, but it would be experimental and I would not trust it to last a long time

> I’m sure what you are saying could be done- especially to basically add stiffness to key regions of a carbon racing bicycle

I reckon it'd be a lot easier to just increase the wall thickness if you want that section of a carbon frame to be stiffer

Not really- even very thick carbon is quite flexible…. It works great for applications where you want that like bendy sailboat masts and front forks on bikes, but it should be cored or replaced with something else if you are looking for stiffness

That doesn't match with my experience. I've got a carbon fibre road bike and some parts of the frame are remarkably stiff whereas other areas such as the handlebars have noticeable flex.

It can be surprising to people just how tough/strong carbon fibre parts can be - here's Danny MacAskill's destructive testing of some CF wheels: https://www.youtube.com/watch?v=VfjjiHGuHoc

If one wants to do that kind of thing it might be better to fill the CFRP with something else-- stiff foam, balsa etc.

Yes, that is how carbon fiber racing sailboats are made

Yes, and it's a kind of standard thing 'sandwich construction'.

If you're thinking of wrapping a material in carbon fibre, why not just use carbon fibre composite in the first place? Is magnesium stronger than CF for a given weight?

Magnesium, especially a casting, can be something like an order of magnitude cheaper. Carbon fiber is an intrinsically more expensive material, and manufacturing complex engineering parts solely with CF, to high quality standards, is almost an artisanal process.

> Magnesium, especially a casting, can be something like an order of magnitude cheaper.

That doesn't seem to be borne out by bike prices - it's entirely possible to buy a very usable carbon fibre bike for approx £1000 but I can't recall seeing a magnesium framed bike for £100.

Edit: looking at cheap frames on AliExpress, you're not too far off. I saw a magnesium alloy frame for approx £80 and a carbon fibre frame for £350. Not quite an order of magnitude though.

I had a Merida Magnesium 909 road bike back in the day. They were common in Australia. Was (wrongly) convinced magnesium was going to overtake carbon. Never had any issues in 10 years of ownership and a lot of kms. Welds looked shocking and it was very rigid and unforgiving though.

Vaast bikes [0] makes magnesium bikes today, I own one (A/1 gravel) and it's a very pleasant ride.

[0] https://www.vaastbikes.com/

I have a Kirk Revolution frame sitting next to my desk waiting to be repainted as I don't like it's turquoise colour. Uncracked as many others out there. Looking at it as a very first puts the issue about cracking bottom brackets into a different light. How many other firsts in any tech do fail and show where the next iteration needs to happen? I think it's quite sad it didn't see any more iterations.

Can modern material science model this computationally, or does everything have to be observed experimentally? This kind of insane just-so recipe - are researchers just iterating on hundreds of thousands of different alloy compositions and production techniques or are there strong theoretical principles on which some of this can be derived?

Its been some time detached from the mat sci folks deeply involved in the space but its both. There is a bunch of theoretical underpinnings but ultimately a lot of throwing darts on the board as well.

Yeah. It depends a lot on the type of material, too. Conventional metal alloys -- like LPSO-Mg -- are the toughest to model. Too many variables. Ceramics and intermetallics are a lot easier to model in principle, but they can have surprising properties on an atomic level, and there's really no predictive method for that sort of thing. Modeling does get you pretty far with high-entropy alloys -- because to a substantial extent their properties hinge on how a bunch of different atoms might fit together randomly, and that's something that can be computationally predicted. A lot of the recent interest in HEAs is because they're relatively easy to model.

Computational materials science is a current research area.

I'm looking forward to a sleugh of articles telling me carbon frames have a really harsh ride quality and lack a certain "je ne said quoi" compared to magnesium frames.

Quite - the grass is always greener.

With modern understanding of composites, and complex layups with UD fibre, the "not comfortable, too stiff" is less and less true. The reduction in road buzz I got when I finally moved to CF handlebars was noticeable.

I learned about this company's magnesium frames recently: https://www.vaastbikes.com/company/

Interesting. I haven’t heard of them. Joining would still be a problem for a bike frame. Any idea on how well they work with other severe plastic deformation processes?

They appear to benefit from ECAP, if that's what you mean. For e.g.: https://www.sciencedirect.com/science/article/abs/pii/S09215...

Presumably they'd also benefit from SMAT and other forms of surface modification.

That said, they're really good as extruded, and they don't appear to benefit as much from SPD as some steel and aluminum alloys do.

How would you fabricate a frame from extruded tubing? Welding would destroy the grain structure.

That looks like it's an active research problem: https://www.sciencedirect.com/science/article/pii/S266633092...

At a glance, though, the problem doesn't seem insurmountable. FSW appears to work.

Brazing has a long tradition in building bicycle frames.

And lugs

Aren’t truck chassis increasingly made with epoxy or other adhesive bonds?

Magnesium is common in suspension forks lower legs.

I thought stiff was a problem with aluminum - stronger is better but is stiffer better?

That said, I wonder if there is a way to make frames more comfortable without having the flex absorb pedaling energy.

I don't believe that the frame material makes much difference to comfort. The part that can deflect/absorb bumps and vibration the best is the tyre. So the answer to your question is bigger tyres at lower pressures.

Tires and to some extent seat post -- more exposed post deflects more than very short posts (like classic steel bike shapes).

Yeah, whenever I hear people talk of the properties of bike frame materials it reminds me of audiophiles: plenty of strong opinions backed by a remarkable absence of data.

A typical bike frame follows a truss structure: stiff and unyielding by design. Vertical compliance is going to be found elsewhere: tires, exposed seatpost, chamois/saddle, fork, handlebar, tape.

Yet, how many roadies do you find talking about suspension seatposts? It's all because in that subculture emulating present and past pro racers is seen as cool, and anything else isn't.

If you are curious, a few people like CYCLINGABOUT [0] and Overbiked Randonneuring [1] have done some measurements and the data suggests that suspension seatposts provide even more reduction in vibrations than wide tires.

[0] https://www.youtube.com/watch?v=u1e3g8uqrJU

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

Yeah, suspension seatposts can provide 20mm of vertical compliance (varies for different models) which is more than you'd get with 28mm width tyres. I have tried a split stem suspension seatpost, but found that that particular design wasn't great as it was difficult to set the saddle up so that it didn't end up tilting as the two parts of the seatpost moved within the frame. I currently use just a standard carbon fibre seatpost that provides some compliance, but isn't a "suspension" type.

How’s it compare to carbon which is the most common high end, lightweight bike material these days?

As of right now, nobody makes LPSO alloys in commercial quantities. Fuji Light Metals has a pilot plant that does small-scale production of extruded strips and plates, but their customers are all researchers and R&D labs.

That said, we can extrapolate from mechanical properties. If we assume that both materials are tubes with the same wall thickness, and that we're looking at T300 carbon fiber (by far the most common type) in epoxy resin vs a standard research grade of LPSO, then:

- The CF will be stiffer

- The CF composite will be slightly less dense (1.6 gm/cc vs. ~1.8 gm/cc)

- The CF composite will have a slightly higher tensile strength, but the difference is very small and could be nonexistent in practice.

- LPSO-Mg will be more damage tolerant -- with better resistance to abrasion and better capacity to flex in a recoverable way in response to extreme mechanical stress. (Cast Mg alloys are undoubtedly worse than CF, but LPSO-Mg is a lot more like an aluminum alloy in this respect. It's a pretty ductile material.)

- LPSO-Mg should in principle be cheaper, though this is likely not going to be the case for a long time.

- LPSO-Mg will have better mechanical damping properties, so might transmit fewer vibrations to the rider.

R.I.P. Sheldon Brown. I'm glad his pages still exist both as useful resource and as a time capsule of what the best of the old web looked like: useful, content rich, no ads, fast loading, stable urls.

I got down to the bit about Sheldon Brown being Harriet’s husband and was “wait that Sheldon Brown?”

That was when I realized what site I was on.

No ads? I assume you have an adblocker installed? Without one, you do see some ads, although by far not so obnoxious as on other sites...

I was at another OG-style web page [1] today, and thought the same thing. I found a Badger airbrush, a 155 Anthem [2], that I completely forget I had.

[1] https://sites.google.com/site/donsairbrushtips/home

[2] https://sites.google.com/site/donsairbrushtips/home

There is an aliexpress ad on top of the page.

It's interesting that trackies in the 70s were trying to reduce weight that much. I don't think it's perceived as especially advantageous these days. The high-ish end track bike I'm assembling now will be a little over 8 kg (almost 18 lb). We also race much bigger gears (typically 95-110 gear inches in mass start racing, bigger for sprinting) than mentioned in the article (72 gear inches). The position that is considered aerodynamic is also much different -- there is much less focus on getting that insanely low, and instead the focus is on being narrow and getting the forearms parallel with the ground.

It largely is the streetlight effect: we all have or can easily get tools to measure weight, we all have significant experience with weight, etc... Aerodynamics are much more difficult, especially in the 1970s where you can't just do some CFD simulations on your computer. There also weren't cheap solid state strain gauges to outfit wind tunnels or the bike drivetrain. Since only tiny aero gains are available without banned aerodynamic devices, there isn't much optimization you can do and need sensitive tools.

Maybe that's just mostly due to the UCI regulations? No point to develop a fully fitted 5kg bike if it has to be 7kg anyways I suppose

Most competition bikes weigh significantly more than the 6.8kg limit, because weight just doesn't matter very much. A lot of state-of-the-art road and track bikes weigh around 8kg.

On the flat, weight only affects you during accelerations - at a steady speed, it has no significant impact on performance. Aerodynamic drag and rolling resistance are constantly sapping away power, so features that reduce these losses are nearly always worthwhile even if they increase weight. Even on a moderately hilly road stage, aero trumps weight by a considerable margin; on the track, weight is almost entirely irrelevant, particularly in longer events.

A lot of riders like the feel of a lightweight bike, a lot of them believe that light bikes are faster, but that's only true on exceptionally steep stages or hill climbs.

So it only matters on basically every classic non time trial race?

Did you ignore the part where GP was talking about the tradeoffs made, and how aero improvements are almost always worth the extra weight?

It's about optimizing the whole system, not just one part of it.

With the speeds the pro's climb these mountains, aero is still a big deal. For you and me slogging along it's almost all weight that matters. But not for the pros.

Keep in mind that arodynamic drag is not a function of ground speed, but airspeed. If you ride slowly in a relatively windy place, your airspeed can easily be twice of your ground speed.

That said, given how many of us are overweight, worrying about a couple of kilos on the bike is funny talk anyway.

I remember hearing Callum Skinner talk about the British track team preparing for the Olympics, and how the biggest problem they had was strength - I remember the number 2400 for their best track sprinters, I forget if that was in watts or newtons but either way it's a massive force and they were snapping frames.

The discipline of cycling that's the most weight-motivated is hill climbing. Track cycling really doesn't have that as an issue, and definitely does have a materials strength issue, so I'm not shocked they're not building to a weight limit.

2400W is plausible for a world class track sprinter.

Unless you can hide away a 2kg battery/motor combo. (Just joking really as they do scan for hidden motors nowadays)

If you have a 5kg bike you can put the extra 2kgwhere you want it. this can make a difference in a race.

If it mattered, though, every track bike would be exactly 6.8 kg -- and they aren't.

Not sure if you know about Merckx's bike for his hour record - they did many interesting modifications to it aiming to reduce its weight

Yeah, Sheldon mentions it in this article. I don't think those mods helped. Weight has no impact on sustained speed.

Rolling resistance increases linearly with weight, so it does have some impact.

Ok. Almost no impact. Worth keeping in mind we're talking about a system weight of like 180 lb vs at most 185 lb here (Merckx was ~163 lb), for a relative difference of up to 3%.

> Weight has no impact on sustained speed.

On a nice track, assuming a perfectly smooth surface and zero elevation change, I'm willing to accept the effect may not matter enough to care. But introduce even just a little bumpiness or some elevation change (perhaps in the track curves), and it might matter for someone pursuing the hour record.

Surface irregularities (bumpiness) are the reason why lower pressure tyres are now preferred on bikes. The idea is that a very rigid tyre will deflect the bike and rider up and down which wastes some energy/momentum as well as fatiguing the rider, whereas a lower pressure tyre can absorb those irregularities and "roll-over" the bumps. This is part of the reason that recent thinking has moved from skinny high pressure tyres, to wider medium pressure tyres. (Wider tyres will tend to roll quicker than a thin tyre at the same pressure - something to do with how the contact patch deforms the rubber).

However, cycling tracks are designed to be very smooth which is why high pressure tyres are still used there.

Any bump results in some energy transfer. In the case of small enough bumps and tires at ideal pressures, most energy is returned, but not all. These losses accumulate. The question is "how much does it add up to?" This is why I recommend using the phrase "negligible effect" instead of "no effect".

You're not going up and down the track during an hour record. Just doing laps at the bottom (zero elevation change). Track surfaces aim to be very smooth in general.

> You're not going up and down the track during an hour record.

Here the English language obscures the physics. Sure, the black line on the track is at a constant elevation. But the tire's point of contact is different from the system's center of mass (CoM). CoM is key here. When a rider tilts in the turns, the CoM lowers. In the straights, it raises. So, you _are_ going up and down during the hour record.

The question now becomes: how much effect does this elevation change have?

It is one thing to be aware of the effect, run the calculations, and find the result is negligible. Has anyone done this? That would be an interesting analysis, and I'd like to see it.

With this in mind, I will make another claim: for a particular rider, there is an ideal line around a velodrome that would minimize center-of-mass elevation change. This line would be faster than the current black line. How much faster? This would be a fun simulation problem.

Another interesting connection: center of mass and bicycling explains why pumping works on a BMX track, a pump track, a trail, and so on. (There are other mainstream explanations, but I think the CoM explanation is the most elegant.)

It’s an interesting question & thought experiment! To the degree that it even matters compared to all the other bigger forces, I would put money on riders naturally adjusting for CoM changes by riding slightly higher during the turns; I’d bet they already take approximately the ideal racing line you suggest. I just watched a couple of velodrome rides on YouTube, and it does seem like riders are often closer to the red line during the turn and the black line during the straightaway, statistically, but it’s noisy and would need to be measured.

The CoM’s elevation change on a velodrome track is due to roll rotation around the direction of travel, not to climb & descent. You can’t pedal harder to recover from a lean, so this is a different kind of up and down than straight line elevation changes. It makes sense that work is being done somehow if the CoM moves up and down, but the turns come with necessary changes to the higher moments of inertia anyway that flattening the CoM elevation doesn’t change. I’d speculate that the ideal CoM line might not be flat, in the presence of mandatory high speed banked turns; the fastest line and the line minimizing CoM elevation change might be two different lines. Do also keep in mind that on a velodrome track, a higher elevation line is a slightly larger radius turn & longer travel path. It’s also possible that trying to compensate for CoM elevation change adds as much time as it saves.

Wouldn't you mainly get the energy back? Like, you use some going up the wall, and then gain it all back going lower.

You slow down incrementally between every power stroke.

A heavier bike would slow down less. At the end of the day the energy is lost to friction.

Wind resistance is the primary force slowing you down at speeds where riders care about such things. The tiny micro-accelerations after every dead zone add up in spent calories when you have a more massive bike+rider system.

That's my point exactly, wind resistance is the principal loss of energy.

The microaccelerations in the dead zone will be lesser in magnitude when you have a heavier bike plus system, but it will be more calories per m/s to recoup - while a lighter system will accelerate easier but have more acceleration to do. In the end the dead zone acceleration are calorically going to be exactly the same no matter the weight.

Yeah I was curious about the weight thing too. The hour record is probably the event in which weight matters the least, since there's no acceleration and no hills.

The pinnacle of the modern tubular aluminum road bike frame was probably reached with the cannondale CAAD8 and CAAD9 frames, which could easily be built into UCI-illegal-weight bikes using expensive components and wheelsets.

stripped example: https://weightweenies.starbike.com/forum/viewtopic.php?t=153...

https://www.reddit.com/r/cannondale/comments/1d9nind/2009_ca...

Every time I’ve visited a Sheldon Brown page, I’ve gone down a rabbit hole.

This time it was “Sheldon Brown’s personal bicycles” https://sheldonbrown.com/org/bicycle.html

That’s the essence of a great website.

I've only just found out that he suffered from Multiple Sclerosis: https://www.sheldonbrown.com/org/ms.html

For me the biggest innovation in bicycles was Graeme Obree -

https://en.wikipedia.org/wiki/Graeme_Obree

With his "old faithful" bike he built himself

I was looking at it in the museum last week and it still impresses me how intuitive he was about cycling. Things like integrating the pedal and shoe to save on height, and also reducing the q-number with the narrow bottom bracket.

I remember doing time trials with Graeme before he had created "old faithful" and he was just incredible

Graeme wrote a book on training a few years ago - its very home brew - but he was ahead of his time saying that you need to ride 25-28mm tyres on the road, rather than the 20-23 which were fashionable at the time.

What was the patent for?

I remember seeing an old aluminium bike in the Manchester industrial museum

This is from 1896 https://collection.sciencemuseumgroup.org.uk/objects/co84092...

And theres this https://collection.sciencemuseumgroup.org.uk/objects/co25722...

Doesn't give a date, but this is the one I remember, and seem to recall it being 1901

I also rode an aluminium frame my granddad owned that was from the 1950's, with weird 700A wheels by today's standards.

> She did spend another year in France, but not until 1988/1989 with her husband, Sheldon Brown…

It's his wife! Harriet is Sheldon's wife!

> Use larger diameter tubular components - Strength goes up as the cube of the diameter so unless there are geometric constraints, use larger diameter tubes with thinner walls to get a lighter structure with increased strength and stiffness.

This trend has continued -- it is very noticeable in road and mountain bikes.

But this trades off against impact resistance, aerodynamics, and the can-it-fit-between-your-legs-metric.

If youre thinking modern carbon frames most of that is actually driven by design for manufacturability, not strength/weight/performance optimizations per se. Off the top of my head:

Frame “tube” dimensions driven by layup mold & mandrel/bladder requirements to minimize tooling and layup time

Press fit to reduce inserts and post mold operations with a “simpler” molded interface

Flat mount brakes to simplify mold shape and support simpler insert components

UDH and direct mount again the simplicity of molded in shape, minimal inserts, reduced post mold operations.

“Modern” UDH hangers move threaded components off the frame. much simpler than the old syntace style which need both precise thread alignment and/or frame tooling operations and/or additional inserts.

You could probably throw head tubes in here too; split races to avoid reaming, molded bare pseudo-press fit “cups”, and the absolute ridiculous sizes like IS47 and larger.

Many/most of those only help manufacturing costs for major frame factories. And are middling to suck for other materials and small volumes. Ex steel flatmount and IS47 is an absolute joke.

My main gripe with those large diameter tube frames is that they're just ugly.

Taste is personal; and of course, you can still buy skinny-tube steel frame bikes, with probably more options available than at any other time in history.

I find the obsession minimizing bicycle weight funny. It's not the bicycle weight that matters, it's the combined weight of bicycle and rider that counts.

Rider weight massively outweighs the relevance of bike frame material, especially in the West where obesity epidemic has biased BMI upwards over the last half century.

That’s what I tell myself when picking the bike - just get a competent basic $700-ish bike, and if you want it 2 kg lighter, lose those 2 kg instead of paying thousands.

In evolutionary terms, being taller, fatter and more muscular is advantageous, but in practical terms it's just a lot of extra weight to drag around for a lifetime, along with all the extra calories of energy needed to do so.

Yep. That's what I keep telling myself. ;) In the end, those will all kill me sooner because they're each opposed to longevity in a safe environment.

Weight isn't that important for bike racing unless you're specifically doing hill climbs. Aerodynamics will make more of a difference, so there might be some advantage in having a bit of belly fat to enable a smooth airflow.

Also, heavier riders are generally faster downhill as they have a greater terminal velocity.

> have a greater terminal velocity

No, unless they're Russian, they're not free falling. They have greater potential energy. And also increased traction, increased rolling resistance, and increased losses in wheel bearings and drive components due to friction.

Terminal velocity can still apply when cyclists are going downhill. Essentially it's the speed that a cyclist will reach when the gravitational force is equal to rolling resistance (roughly proportional to speed) plus the air resistance (roughly proportional to the square of speed) assuming that they're just free-wheeling and not pedalling. If two cyclists have a similar air resistance, but different weights, then the heavier cyclist will reach a quicker speed. There's the argument that a heavier rider will be bigger and thus have more air resistance, but that effect is smaller than the weight difference. (NB. this can be trivially tested).

Terminal velocity still applies. Yes, it is because they have more potential energy (per CdA).

Rolling resistance increases are pretty marginal with compensating tire pressures (i.e., higher). Wheel bearing losses are de minimis.

Drivetrain component friction is not a function of rider weight.

> Drivetrain component friction is not a function of rider weight.

Wheel bearing friction, duh. If the rider stands up while pedaling, it does. :)

Yep. A heavier bicycle is cheaper, less fragile, and also increases the workout effect. As long as a bicycle isn't 20 kg / 50 lbs, what is the real problem? I believe the real goal for lightness is luxury conspicuous consumption to maximize cost using exotic materials like beryllium.

> and also increases the workout effect

If you push 300W on a 5kg bike or 20kg bike, the "workout effect" will be the same.

At the end of the day, if you are looking for "workout effect", it means that you're trying to achieve something, like winning races or going faster.

And for a given rider, with a certain weight and certain physiological abilities, they will go much faster on a 5kg bike than on a 20kg bike.

There is a whole world between <$1k bikes and those >$2k ones. Weight being an important part. Not only because it reduce the total weight of bike + rider, but also because a 5kg bike behave in a very different way than a 20kg.

It's like saying that cooking with a chef knife is the same as cooking with a sword.

Sure, after a certain point, the race for removing a few grams here or there is a luxury and many people tend to believe that spending $$$ on a lighter bike will fix their lack of fitness.

But modern bikes provide a completely difference than the old, heavy ones.

It's not bike weight per se, but there's also a somewhat direct link between weight and component quality and age. I.e. no one really tests a 20y old bike with current top-end components, no one really puts 10y old groupsets on a 2024 frame.

Yes, rider weight trumps it, but modern bikes in general just ride nicer and most of us who are not pros only test a dozen different bikes at most. It's a hobby, people like to splurge.

Depends on what you're using the bike for. If it is for work or transport (as it used to be for paperboys and delivery gigs a few decades ago), you'd want it to be as smooth and light as possible.

In Tyler Hamilton's book he describes going out for hour long rides, then taking some sleeping pills and going to bed, all without eating, just to shed weight before the tour. Just crazy.

Just an anecdote thats been horrifying me for the last week since Klein is mentioned.

I learned last week that my colleague bought a commuting bike from an old friend. A true once in a lifetime barn find. Mid 90s Klein Attitude, only used for a few weeks before being stored in the barn until 2023. My colleague is currently putting it through its second winter on salted, snowy roads.

I'd much rather see a bike used for a purpose than a bike lost in the back of a barn!

What's the alt. timeline for the bike? Stored as a collectors item?

Ships in the harbor and all.

Bikes are for using, not sitting in barns.

Gary Fisher has an insteresting paper too about alu frames:

https://web.archive.org/web/20061103174315/http://www.kleinj...

I'm convinced titanium is a pretty optimal bike material. I hate aluminum frames, too stiff, some amount of flex makes a bike so much nicer. Hate carbon, too. Steel is nice.

I've have a lite ghisallo frame which I think was under 2lbs. The whole bike is under 15lbs and still manages to carry my 200lbs of weight.

> I'm convinced titanium is a pretty optimal bike material.

I'm less convinced. Firstly, I'm not convinced by the frame flex theory of ride comfort - I believe that the tyres are by far the biggest contribution to ride comfort due to the amount that they can flex which is far more than the tiny amount that the frame can.

Secondly, aerodynamics is far more important (if you care about speed/effort) and titanium is tricky to get into highly tailored shapes unless you resort to fancy 3d-printed frames.

Carbon would be my choice due to the design flexibility - by orienting the carbon fibres differently, components can provide strength/stiffness in one direction whilst allowing for compliance in other directions. Also the shape can be relatively easily changed - no need to always use circular tubes.

It'd be interesting to see a 3d-printed titanium frame that uses some kind of honeycomb internal structure to provide super strong/light frames, but I suspect it would be exorbitantly expensive.

I share your skepticism about Titanium as a frame material, both in terms of comfort claims and tube shape limitations.

However, you might find this interesting -- No. 22 bicycles has a (very expensive, prototype) titanium aero bike: https://22bicycles.com/products/reactor-aero . It hasn't actually seen a wind tunnel but at least it looks like an aero bike and they're talking about putting it in one. It is made using 3d printing (additive manufacturing) at least in part.

> Pricing for the final production version has not yet been finalized, but we anticipate a frameset (frame, fork and headset) price in the range of USD $10,000 to $15,000.

Titanium frames have a devoted fan base. Personally, I tried to notice the difference back when I did road racing but didn't. Maybe I didn't want to: Ti ain't cheap.

Custom ti frames are cheaper than the high end carbon frames nowadays.

What is cheap these days?

Low quality steel is very cheap but also really heavy. You can get a whole crappy bike for a couple hundred bucks. Higher end steel isn't as cheap but is still relatively heavy (compared to aluminum or carbon). You can get this kind of bike in the $1000-2000 price range (e.g. Surly). Aluminum bikes tend to be inexpensive, but also not the lightest. These can also be priced at $1000-2000 (Specialized, Trek, Giant, ...). Carbon comes in a range of prices with various tradeoffs. You can get very budget carbon frames at like $1500 (Winspace) or whole bikes at like $3000 (Giant) (maybe $2000 in non-major brands, very discounted during current market conditions).

For titanium, I'm seeing Black Friday deals starting at like, $3200-3500 (Lynskey / Litespeed). But they're often sold at higher prices than carbon bikes. (For my money, I prefer carbon frames -- you get more flexibility in tube shapes and the end result can be lighter and stronger than titanium.)

Check these out https://www.rodbikes.com/profiles/profiles.php?tag=ultra-lig... steel bikes ~13.5 lbs.

Yeah. Very expensive and with significant compromises.

could you expand? I get the expensive part, but they're also hand built customs so...

Rim brakes are not great in wet conditions and limit tire sizes to about 28mm. Lightweight steel tends to be flexy and susceptible to dents.

definitely with you on rim breaks... I thought they mention in one place they can put discs on these. I'm a large person and live in Seattle so I've been rocking discs on a cyclocross style bike since 2010 back when everyone was anti discs, they're far superior glad people finally got sane about them.

> I thought they mention in one place they can put discs on these.

Yeah, they can do it, but they'll be a little heavier than those relatively light rim brake steel bikes linked earlier. (The rotors/calipers, hydraulic, fluid, stronger fork leg required all just add mass.)

I'm also in Seattle! Disc brakes all day.

For about the last year and a half you can usually get a carbon road bike from major brands with basic components starting from 2000 euro (right now I see Bianchi, BMC, Cannondale, Cube, Giant, Specialized listed around that price).

Yeah, I think in particular prices have come down dramatically in the past 3-6 months.

The specific 2000EUR figure might be European pricing. The lowest I'm seeing for any carbon road bike from e.g. Specialized with US pricing is $2400 for a two generation old Tarmac SL6 (this generation was current 2019-2021) or $2800 for a current Roubaix. The least expensive carbon road bike offering from Giant is $3300 US (TCR or Defy). (Though I'd expect to be able to find better deals at retailers trying to move old inventory than direct from the manufacturers.)

Yeah EU. One example I can give is this, Specialized Aethos 2024 for 2200 but only one size available, Giant TCR Advanced 2024 several sizes 2400, plenty others. This is a reputable retailer and there are some other with same/lower prices.

https://www.bike24.com/road-bikes.html?dynamicAttributes%5B2...

Prices shot up during the pandemic and never really went back down. You're lucky to find a good carbon bike for under $4K these days where you used to be able to find them for $2K.

Everyone's in oversupply now, inventory is listed at steep discounts to 2022-2023 prices.

This bike isn't even on sale and it's under $4k and not a bad bike: https://www.giant-bicycles.com/us/tcr-advanced-2-pc-2025

Quality used bikes are remarkably affordable. I'm a sucker for 80s road bikes; $200 gets you something decent, bring it to a shop for a tune up and probably new brakes.

10-speeds are most common, so you have to be ok with that; although some vintage bikes did have 3 chain rings. Older road bikes tend to have narrow tires, because everybody thought they were faster; 1/4" tires are workable on unpaved mixed use trails, but 1/8" will be pushed around easily by tree roots and ruts.

Frame flex of ti bikes is pure fantasy/placebo (at least on the vertical plane) on traditionnaly shaped frames.

You would need enough force for the tires, wheels, saddle, handlebar, stem and seatposts to break/explose before the double triangle start flexing.

You wouldn't feel the stiffness of an aluminium frame as much on a track. On the road, stiffness is a more important factor for rider comfort.

Ti is difficult to weld - there are a lot of cracked Ti frames out there - often at the welds :( A shame as they (can) look great.

With all the mods ("hardcoded" seat, no stem, custom shafts and bearings) It's funny he decided to keep the toe clips -- would've easily shaved a few ounces there!

Two things jumped out at me: the simple/non-adjustable saddle support, and the absolutely slammed bars affixed just above the fork. Was that normal for track bars at the time?

Check out the Soviet Takhion [1] track bike for a similar handlebar setup.

Cinelli also had a version of their legendary Laser [2] bike with that setup.

1: https://bikecult.com/works/archive/03bicycles/takhionVVVV.ht...

2: https://www.pedalroom.com/bike/cinelli-laser-aero-pursuit-34...

Great references! Thank you.

Yeah, both are relatively insane choices by modern lights. You see some other track bikes of that era with fork-mounted handlebars (it's not unique) but I believe conventional stem + bars were more popular.

Tbh I love the simplicity of the hard coded saddle post + support. Both being made out of the same tube size.

aluminum is nice, yet once in a blue moon you get something like this year an aluminum hiking pole broke when i lost my balance on a slippery slope and put a lot of weight on the pole and falling i almost got skewered by it's broken off jagged lower piece. I really want steel poles now, yet can't find them to the point of pondering DYI-ing from some Home Depot steel tubing.

That's a problem with aluminium - no fatigue limit. This means that cyclic loads on an aluminium frame (or pole) will eventually cause it to fail. Steel does have a fatigue limit such that cyclic loads below that threshold won't cause eventual failure.

There's some good info on bike frame materials here: https://bike.bikegremlin.com/11144/bicycle-frame-materials-e...

It is only really an issue with aluminium forks and non traditionnal construction.

With a "diamond shaped" traditionnal cycling frame you have nearly 0 chance of a frame failing catastrophically. Usually the weaker part crack and your bike just end up creaking horribly and/or feel noodly. I have suffered and witnessed a number of alu and alu+carbon bonded frame failing at the glued joints.

Wasn’t this solved by Klein?

Carbon hiking poles are the way to go, they're very light and very affordable.

A modern alternative are bamboo frames, e.g. https://my-boo.de

Whilst bamboo is an interesting "green" material, it doesn't really compare well to a carbon fibre frame. Modern thinking is that the frame weight is secondary to aerodynamics and one of the advantages of CF is that the frame "tubes" can be shaped specifically to help with that. Of course, the main aerodynamic advantage to be gained is from the human sat on top of the bike.

I was going to say it looked like a Cannondale TT. It was too stiff, unstable, difficult to control, and rode poorly compared to heavier steel frames. Steel is heavier but at least you'll still have teeth left after a ride on a road that isn't perfect like a freshly-asphalted bike path.

Favorite road bike I’ve ever owned was the aluminum Klein Quantum Race designed by Greg Klein.

Klein bikes of that era had the best paint jobs I have ever seen. I was way too young to even know about these bikes back then, which is a shame, as they are pretty much at the very top of what constitutes bike porn for me.

Yeah they were good

Don’t need a bike manufacturer to do that for you though

I still own a Klein Performance ‘81 and an Adept Comp that has its own amazing story. Love Klein bikes. In fact, I kind of expected this article to be about Klein since it also came from MIT in 1975.

https://en.wikipedia.org/wiki/Klein_Bicycle_Corporation

nice story but the ads are awfully annoying, and b4 u suggest an adblocker, I’m on a phone.

I suggest an adblocker for your phone

I was browsing this page on my smartphone in an airport with the ublock origin extension blocking the ads...not sure what you are talking about with that weak phone excuse.

Various VPN services provide ad blocking and a phone app e.g. Mullvad

It’s not perfect, but carefully choosing DNS resolvers/profiles can get you a lot of the way there.

Even Mullvad ad-blocking DNS is available for free, no app (and def no account!)

https://mullvad.net/en/help/dns-over-https-and-dns-over-tls

Nice thing is you can set your DHCP to hand this out to all devices.

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