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Comment by thomasfl | Hacker News Reader

The most important fact is that riding a bicycle is 3 to 5 times more energy efficient than walking. Depending on the road, bicycle, terrain and weight of the rider. Riding a bicycle is the most efficient self-powered means of transportation.

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

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It's no coincidence that other human-powered transport mechanisms (aircraft, boats, etc.) commonly use pedals for the drivetrain. It's a lightweight way to use the body's strongest muscles, especially when high power is critical.

See:

https://en.wikipedia.org/wiki/MacCready_Gossamer_Condor https://en.wikipedia.org/wiki/MacCready_Gossamer_Albatross https://en.wikipedia.org/wiki/MIT_Daedalus https://en.wikipedia.org/wiki/AeroVelo_Atlas https://en.wikipedia.org/wiki/Hydrocycle

I wouldn't say it's common at all in boats. The two main human-powered boats are canoes and kayaks, and both use the arms, not the legs. There's also rowboats, which again use the arms. Pedal-powered kayaks do exist, but are rare.

It would make more sense to use the legs, but it's a much bigger engineering challenge than making a simple paddle and a boat that floats with no holes in the bottom.

Rowing is not solely an arm mechanism but his actually driven by the legs

As a rower myself I wanted to type the same correction initially, but then realized that the parent comment is probably referring to a rowboat rather than a racing shell. No sliding seat, no leg drive.

Rowing in a real rowboat has little to do with the legs: the seat is fixed. It has a lot to do with the back, however.

"Rowing machines" have very little to do with real rowboats. Real rowboats don't have sliding seats.

Sliding seats are used for competitive rowing. For example: https://en.wikipedia.org/wiki/Rowing_(sport)#Technique

When normal people talk about a "rowboat", this is what they're referring to:

https://images.app.goo.gl/UsSUQCWLLNPmkDf39

That's certainly true--oars are by far the most common configuration for human powered boats. I was thinking more about human powered boats that set speed records, e.g. the Decavitator

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

A lot of this might just be because Mark Drela, who was involved in the design of several of the aircraft and boats on this list, is a cyclist.

I had a look and the source cited for it being the most efficent self-powered means of transportation is from March 1973; I wonder if there's been any new developments since then.

Random things off the top of my head: Some time ago they built a self-propelled helicopter, which also used bike technology (gears etc). I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human body - it is (or can be) a full-body motion, including the large muscles in the back and legs and the smaller ones in the arms, while cycling mainly uses the legs. But the mechanism to translate rowing energy into the propellers was too heavy, or something like that.

Actually it might have been a HN thread. Here's one from 10 years ago, and it just so happens that I had made my account by then so this was probably it: https://news.ycombinator.com/item?id=6028326

In terms of efficiency of bicycles alone, aero frames, deep wheels, carbon fiber.

Clipless is also an incredibly significant change, but not as much of efficiency as the others.

Carbon fiber?

As I understand it, reducing unsprung weight (which is not very much for a bicycle with no suspension beyond the tires) can have an outsized effect, but actually reducing weight mostly matters for ascending. For non-competitive cycling, other factors seem like they should be much more significant.

A big one, which is banned in most competitive formats, is a fairing. This is much more effective than having a human hunker down and try to be aerodynamic. Even for an upright cargo bike (which is generally extremely heavy), a fairing in front can make a dramatic difference on level ground with no wind.

Carbon fiber isn't better because of strength, but because it's a lot easier to keep somewhat light while making aerodynamic shapes.

The most important is carbon wheels. Lowering the weight of the wheels makes it easier to turn them, especially uphill.

It’s only a slight improvement when accelerating. At steady state, the wheel weight is balanced out (half moves backwards, half moves forwards).

GCN have done some non-scientific experiments on their YouTube channel on this.

The biggest benefit to carbon wheels is you can make them deeper for less weight penalty (vs aluminium) which gives you a significant aero benefit.

It's also very stiff so less power is lost due to the flex of various parts.

Which is great if one is racing but not so much for long distance riding or riding for the joy of it. Most riders are not racing at any level where it makes a difference. A well made steel frame is a joy to ride. They are incredibly comfortable and track exceptionally well, unlike stiff frames.

Recumbents are noticeably more efficient than uprights. In fact any tech or method that's been banned by UCI should make bikes even more efficient.

carbon fiber is a lot less efficient regarding manufacturing though, compared to aluminum. The difference is even bigger with respect to steel or the life time of the materials

The idea is older:

https://en.wikipedia.org/wiki/Human-powered_aircraft

If we take distance passed as a measurement, intuition tells me that bicycle is more efficient, since it doesn't have to lift the whole body, just move it around on wheels which provide very small friction.

Perhaps if we had bicycles with comfortable seats we can recline in, we could save up energy needed to balance our body on a bicycle. Something like a pedal boat, but with wheels.

Wouldn't that be a simple mod to a recumbent bike?

Honestly, this is the first time I've heard that word. Pretty expected that someone came up with it already, in retrospective.

check out velomobile, recumbent bicycles with a fiberglass shell that can go crazy fast (60km/h is not unheard of).

And 144km/h is possible, but only for the world record holder:

https://www.cbc.ca/sportslongform/entry/the-worlds-fastest-h...

60km/h is sprint speed for elite cyclists on road bikes, I guess recumbent bikes can go way faster than that.

I hit 90 km/h on my recumbent as a fat bloke loaded up for touring. It was on a downhill though :).

At high speed on flat ground aerodynamics matters significantly more than weight, so velomobiles tend to be a lot faster.

Uphill is a different story.

Faired can cruise at 60km/h on the flat at similar effort to 25km/h on a road bike. Marginally slower on steep uphill.

Unfaired won't have you going much faster, maybe +5km/h on the flat and -3km/h on the uphill.

I see them on the street fairly often.

Recumbent bikes definitely are more efficient due to aerodynamics if nothing else. I suspect being able to push back against the seat helps too, though.

I've seen a few of them in the city. The seem great, but I wonder how well they steer. They're low to the ground and seem less visible (I've seen them with flags). On a bike your center of gravity isn't much higher than walking, and you can put your feet out quickly and essentially be in a standing position .

They steer well enough for bike trails. Longer (e.g. tandem) ones may have some challenges with tighter turns (need to do a 90° adjustment at a light).

Flags are common for recumbent for visibility.

The lower center of gravity and the "it's real hard to fall off" can make it useful for people that have difficulty with balance. The back seat of a tandem is suitable for someone with needs for additional assistance ( https://www.terratrike.com/product-category/accessories/assi... ) - my mother would go tandem with one of her friends who was legally blind and needed to use a walker.

I bike A LOT -- >1,000 a month on a 29" full suspension e-bike (Orbea Rise)

But I have been biking daily for morethan a decade, and was a daily bike commuter in the bay area for ~15 years....

I see many recumbent bike a day when on the trail. At least >5 a day.

My house backs up to the American River trail, I literally leave my house and get directly onto the trail in less than 2 mintues.

Recumbents are all over the ART in the Sacramento Area.

One thing I have noticed though, and this is just a statistical observation on my part biking that trail regularly for ~2 years...

The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.

They look fun though. I'd love a long distance camping -e-bike version of one with a trailer and a detachable, light, curved windscreen that can be put on the top of the trailer when one wants.

> They look fun though. I'd love a long distance camping -e-bike version of one with a trailer and a detachable, light, curved windscreen that can be put on the top of the trailer when one wants.

https://bikeportland.org/2009/11/10/portlands-terracycle-unl...

That company appears to be https://t-cycle.com

> The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.

Recumbents also used to be far more expensive than standard bicycles (although now there's a lot of expensive standard bicycles) so an older demographic isn't surprising.

Recumbents are also lower in height and a lot easier on people's joints so are particularly good for people who have medical issues or mobility impairments. So, again, your demographics aren't surprising.

Yeah, no slight on recumbents! I want one.

Oh, and the other demo is 100% of them are wearing 'Gardening hats' (A hat you tend to see people gardening in...)

> The average Recumbentist is a White Male, Typically with a beard >50 years old, 30% are overweigth, 30% are average build, 30% look semi/more-fit, 10% are female.

I'm white, male, beardless, and 40 and am almost always the youngest when showing up at a recumbent meetup.

A lot of the current crop of recumbent riders (in the US at least) got into it in the late 90s and early 2000s. As the boomer cohort aged out of riding two wheeled recumbents there was a significant drop in demand for recumbent bicycles and a corresponding increase in recumbent tricycle demand. The companies making fast/racing recumbents stopped due to lack of demand (basically just Performer and Bacchetta are left) so there aren't a lot of us left in the fast recumbent bicycle crowd and almost everybody is running a 10+ year old bicycle. I have a 2009 Optima Baron, for example. More casual recumbent bicycles like LWBs or crank forwards are still around and seem to be more popular in the midwest than on the coasts. I live in NYC and recumbents are particularly rare here due to the downsides of recumbents in the city, mostly sight lines in traffic. I've seen 6 in the wild in the last 8 years and I usually see 4 or 5 recumbent trikes on mass rides like the 5 Boro but all the trikes have been from out of town.

This is true - the ergonomics as well as the aerodynamics are a step up. I would like to note though a disadvantage in ergonomics when it comes to hills, which nicely illustrates another feature - often unacknowledged - of conventional frames. I live on a hill and commute on a conventional/non-recumbent bike. There used to be a bearded white middle-aged guy living half way up our hill with a recumbent and I noticed the recumbent seemed way /less/ efficient on our hill climb. A secondary design feature for conventional bike geometry is how well it works on a hill when you stand up. There’s something about how you can use your weight, pulling on the handle bars at the same time as rocking the bike frame side to side, to maximise downforce on the pedals, that just works incredibly well for propelling yourself and the bike up a hill. None of that is available on the recumbent designs I’ve seen, and because the hill slows everything down, they get less aerodynamic advantage too. So while they’re great on the flat, I think a key limiting factor for recumbents may be that they’re not so good in hilly places.

Ran into a fellow touring once with a recumbent and a trailer for his dog! All told, a 250lbs rig, few would be able to celebrate as much getting to the top of santiam pass in oregon (approx 4000 ft climb)!

The main losses are drag and, at low speeds, friction.

A velomobile (enclosed bicycle or tricycle where you lie back) mostly solves the former. The effort of a light walk moves you at about 30km/h on the flat (but slightly slower than walking on a steep uphill).

Steel rails would make it slightly more efficient again.

I read somewhere (lost to the fickle beasts of memory and time, of course) that rowing and the like is not particularly effective, precisely because it requires big, slow movements against resistance, which the human body is not that efficient at[1]. What we are efficient at is quick, light, repetitive movements – like pedaling with the proper gear selected. This is why Ivan Illich phrased it as the bicycle being "the perfect transducer to match man's metabolic energy to the impedance of locomotion".

[1]: This is also why rowing and weightlifting are such a good type of exercise to get stronger, and why bicycling requires that you put in a lot of hours to get stronger from it.

> I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human body

The limit for athletes is normally cardiovascular, commonly oxygen - VO2max the the measurement there. For less fit people it can be the cardio side, their heart just isn't up to it so their muscles fail and they lie on the ground twitching. Oxygen-deprived people pant and gasp.

So recruiting more muscle groups really doesn't help. What does is increasing oxygen intake, and this is where recumbent bikes come in. The laid back position opens the thorax and increases effective lung capacity. As well as reducing air resistance, except that that's a very subtle thing that mostly depends on the rules governing the sport in question (fairing on bike and kayak, for example, are variously restricted or banned in most relevant sports).

You can also reverse that and exercise at high altitude... less oxygen for everyone!

> So recruiting more muscle groups really doesn't help. What does is increasing oxygen intake, and this is where recumbent bikes come in. The laid back position opens the thorax and increases effective lung capacity. As well as reducing air resistance, except that that's a very subtle thing that mostly depends on the rules governing the sport in question (fairing on bike and kayak, for example, are variously restricted or banned in most relevant sports).

Recumbent riders generally have much lower peak power and ftp but higher sustained so VO2 differences wouldn't explain it. The main attribution I've seen is aero and marginally less muscle power used for motions that aren't related to pedalling.

My limited experience is that it's easier to recruit more muscles on an upright, so your peak power can be higher. In my 30's I would hit double for a 30s trial on an upright vs a recumbent (last time I had a decent power meter was in my 30's). But over 5 minutes the recumbent was better even if both were fixed to stands. So I don't think it's the balance issue.

For an hour or more the recumbent wins just for comfort, and unfaired records it wins on air resistance (that's why the UCI banned them, it let povo scum beat gentlemen athletes). But then the UCI doesn't have faired records... it's only the IHPVA et al that make that distinction.

Interestingly the PBP etc records (we don't have records, this isn't a race!) are all uprights AFAIK. But that's xenophobia rather than technical skill from what I know. And the Round Australia record is an upright, largely because no-one on a recumbent has been inclined to attempt it. RAAM is held by a bent (https://en.wikipedia.org/wiki/Race_Across_America#Records).

Recumbents are notoriously difficult to ride as the grades get steeper. Upright cyclists have the advantage using different body positions (i.e. standing), but 'bent cyclists can't do that. On the steepest grades, it can be a challenge to even keep a 'bent's front wheel on the ground.

Sure but then you have to ride a recumbent bike like a dork.

> the source cited for it being the most efficent self-powered means of transportation is from March 1973

what was the source please? ive actually tried to track this down for the steve jobs quote but couldnt find it

I had saved the chart here, Google reverse image search led me to this article https://streets.mn/2014/05/22/chart-of-the-day-travel-effici... which says it's from Scientific American.

There were a few other hits as well. This one mentions the Steve Jobs quote and corroborates "Scientific American, 1973" https://www.smestrategy.net/blog/using-the-6-thinking-for-st...

Only on flat smooth surfaces which are a relatively recent invention. Take them on any natural environment and it falls very quickly below walking.

The difference between riding on grass and riding on a dirt trail is VAST - grass is like 3x worse; but when that dirt trail turns into a mud trail, the grass is better.

Humans made trails by walking for eons before roads were envisioned. Maybe for a chariot you need a proper road, but a human made trail is just fine for a bicycle.

Not only just fine but often times way more fun!

I rode my mountain bike A TON as a kid, gave it up for the more "prestigious" road cycling as an adult, but maybe 2 years ago bought a mountain bike to ride with my kids.

My goodness it took about five minutes on a local trail to feel like that same little kid I was back in the day, the feeling of speed, focus, and flow. There's nothing really like it for me, as it puts me square in the moment.

I hope you're not implying that people in countries with hills don't use a bicycle because that's not true ;-) Check Denmark and Sweden for instance.

Denmark doesn't have hills. It might have "hills", but not real ones. The same goes for the inhabited parts of Sweden.

Colombia could have been a better example, they have real mountains and people over there do use bicycles to do their thing. Granted, not a great percentage of the population does it because you do need to be really fit in order to handle 10% slopes, but of those that do you might get future Tour de France winners.

Egan Bernal already won in 2019 (and before that Nairo Quintana was second in 2017).

Yeah, I was thinking at Bernal when writing my comment. As far as I know he used to bike to school when he was a kid, and he wasn't living in the flat areas of Colombia.

The record for the Tour Divide is about 13 days for 2700 miles from Canada to Mexico down the Continental Divide.

Back in the 80s Steve Jobs cited this fact in an interview and used it for one of my favourite metaphors: A computer is a bicycle for our minds.

https://www.youtube.com/watch?v=ob_GX50Za6c

And, in the very very long term 200yrs+, it's one of the few truely sustainable forms of transportation.

I think it is closer to 9-10 times (on level asphalt road on a "normal" bike) although it heavily depends on some factors like speed, type of bike and your proficiency, terrain and type of ground.

Riding a bike is most efficient at a certain speed and becomes less efficient very quickly as you get faster. So when I mean 9-10 times more efficient, I mean a person walking at a comfortable speed vs cyclist riding at a comfortable speed (on relatively level asphalt road).

Steve Jobs studied movement efficiency, and that’s was why he called the Macintosh a “bicycle for the mind”

https://www.themarginalian.org/2011/12/21/steve-jobs-bicycle...

"studied" is a strong word. he read an article once and then talked about it for the rest of his life because it suited his pitch. i doubt he cared about the scientific veracity

man, Jobs would have killed on VC Twitter, huh

Recumbent bicycles in particular.

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