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There are arguably few graphs that have done as much reputational good for the bicycle as the graph published in Scientific American in 1973.
Included as part of an 11-page essay on bike technology, the graph showed that a cyclist “ranks first in efficiency among traveling [sic] animals and machines in terms of energy consumed in moving a certain distance”. The study also estimated that the energy consumption of a person cycling was a fifth of that of someone walking, and that swimming animals (fish) were most efficient at moving due to their natural ability to float in water, reducing the “fight” against gravity.
Much of the efficiency stems from the coasting along that the wheels enable. Where walking requires a constant expenditure of energy, cycling on flat terrain does not require constant pedalling.
The graph, as reported by Carlton Reid in Forbes, went on to inspire Steve Jobs’ famous quote describing computers as “bicycles for our minds”. Now, on the occasion of Scientific American’s 180th birthday, the graph has been updated.
Bicycles “turn humans into this hyperefficient terrestrial locomotor because they make being on land more like swimming,” physiologist Tyson Hedrick told SA, noting that the aerodynamic disadvantages that comes with riding a bicycle can be slashed even further on a velomobile, a recumbent bicycle with an outer casing intended to reduce drag that reportedly enables humans to move with “even more aquatic efficiency”.
Shoutout to this chart for prompting me to google “Velomobile”. pic.twitter.com/5LetA17DpW
— God For Breakfast (@GodForBreakfast) October 16, 2025
For all the technological advancements of the last 50 years however, S.S. Wilson’s diagnosis of the bicycle’s place in society, as outlined in his 1973 essay and quoted by Reid, couldn’t be much more relevant today.
“Since the bicycle makes little demand on material or energy resources, contributes little to pollution, makes a positive contribution to health and causes little death or injury, it can be regarded as the most benevolent of machines.
“For those of us in the overdeveloped world the bicycle offers a real alternative to the automobile.
“If one were to give a short prescription for dealing rationally with the world’s problems of development, transportation, health and the efficient use of resources, one could do worse than the simple formula: Cycle and recycle.”
-1024x680.jpg "“Clear anti-cyclist bias”: Lawsuit filed against Toronto police after cop doored cyclist… before ticketing rider over incident")
58 thoughts on “Bicycle confirmed as most efficient mode of travel, 52 years after study first showed the benefits”
Chapeau for them reminding us
Chapeau for them reminding us (even though if you think, it’s probably not shocking).
Of course this has little bearing on human affairs. If they could make trendy salmon that would do the shopping run cheaply enough or fit in-horse entertainment systems people would no doubt use those.
* When you think of just how much engineering, infrastructure and frankly “remapping society” has gone in to making it so that people pay lots of money to sit in small boxes powered by explosions to drive over tar and gravel (often quite a distance) to giant warehouses for food etc…
Why is “human on velomobile”
Why is “human on velomobile” to the left (lighter) of “human on bicycle”? A light velomobile is about 70 lb / 32 kg.
Also, I want one.
Human on velomobile weighs
Human on velomobile weighs the same as human without velomobile. I too want a zero-weight velomobile.
The salmon is also suspiciously small, at about 50g and outweighed by the lemming…
DJameson wrote:
Well, it’s never just one lemming, is it?
andystow wrote:
Obviously two different humans – me on a bicycle would still be 20kg heavier than Mrs H on (or is it in?) a 25kg velomobile.
In.
In.
25kg and below is no longer unheard of in “production” ones (eg. made in the 10s to a few hundred as opposed to 1 or 2!). Although on the average of what’s *current* I think you’re right that heading towards 45kg difference would involve picking an older or specially chunky one – even the quattrovelo with four wheels doesn’t get there. But of course you can add all kinds of trimmings, a child in the back, your shopping…
Following graphic is old now but shows some of the diversity https://www.notechmagazine.com/2014/11/the-big-velomobiles-graphic.html
But “on” a naked recumbent, I
But “on” a naked recumbent, I assume?
Chacun à son goût. Mostly
Chacun à son goût. Mostly “on” my short-wheelbase not-super-laid-back 2-wheeler Speedmachine.
But sometimes it does feel more like getting into it.
I suspect something like this is a more “into” experience but have never tried (I’d love to – but it’s clearly aimed at more dedicated folks than me). https://www.darkerside.org/2015/06/short-review-m5-carbon-highracer/
Also want to see where other
Also want to see where other 2-legged designs fit – kangaroos (apparently their hopping mode is highly efficient), ostriches / emus.
I guess soaring flight is not really covered here, presumably eg. a vulture would rate as inefficient because it’s not super aero in powered flight?
And what of other pelagic fish (some noted for high speeds so presumably low drag?), whales (slow but they keep going)?
And further – can the weight-bearing abilities of ant exoskeletons inform eg. cargo bike design?
Kangaroos are up there
Kangaroos are up there amongst the land animals, and switch between hopping and pentapedal locomotion at the speed at which the efficiencies favour one or the other.
Soaring flight doesn’t really fit in, because the source of energy is external (thermals or wind over waves/slopes). In terms of its own wing-flapping power, a vulture can only just maintain level flight at its optimum speed and can’t keep itself going faster or slower – even that puts it deep into anaerobic territory, and they can have trouble getting airborne. But once it catches a thermal, it can gain altitude for almost zero energy expenditure. If you analyse that as though it’s a closed system, it makes no sense because it’s creating energy from nothing. You need to factor in its external power supply, at which point it doesn’t fit on the graph. But soarers like vultures and albatrosses are extremely aerodynamically efficient.
And indeed, big swimmers are very efficient. While small sea creatures lose a lot of energy to the viscosity of the water, that effect diminishes with size (increasing Reynolds number), so whales are outstandingly efficient movers.
chrisonabike wrote:
Actually our cetacean cousins aren’t that slow, orcas can hit 50 km/h+ and fin whales, second biggest species, 45 km/h in short bursts, comparable to the top speed of a Trident submarine and quite extraordinary when one considers their size and water drag.
Rendel Harris wrote:
Actually our cetacean cousins aren’t that slow, orcas can hit 50 km/h+
— chrisonabike
Dolphins can hit 60 km/h apparently. Not shabby for a whale.
Useful for getting clear of
Useful for getting clear of the Orcas…
Perhaps the bicycle has been
Perhaps the bicycle has often been bypassed *because* of its efficiency?
Seems that “transport” is bound up with prestige.
While lots of “going” is mundane, we are quite concerned about going to visit other humans and how we arrive is clearly important.
Motor traffic is far better aligned with that goal – arrive in something big and clearly expensive, ideally which makes noise, and emerge unruffled. (Of course helicopters are now an option…)
And conspicuous consumption has long been important in human affairs. Plus in business (and influencing politics) an industry which concentrates much larger sums of money (motoring) has the advantage!
road.cc wrote:
Physics has left the chat, as the kids would say.
Are bicycles only efficient when they’re coasting? Are track bikes less efficient than geared bikes because the former can’t coast at all?
Cycling is more efficient than walking because the latter wastes a higher proportion of muscular energy—i.e., fails to convert it into forward propulsion. Walking wastes a large amount of energy due to 1) constantly shifting the body’s center of mass up and down and 2) deceleration (using muscular power to arrest your body’s forward motion each time a step lands) and re-acceleration with each step. By contrast, cycling minimizes waste via 1) stabilizing the center of mass and 2) efficient bearings, drivetrain components, tires, etc. that siphon off less of the supplied energy—but on flat terrain you still have to pedal to supply any energy that’s eventually going to be used.
Simply put, coasting merely instantiates the efficiency; it’s not responsible for it or essential to it.
LookAhead wrote:
Well, in one sense obviously not because whilst pedalling the same sized gear at the same cadence on identical bikes it doesn’t matter if they are fixed or freewheel and therefore equally efficient, but that’s not the only way of measuring efficiency; if efficiency is measured as the distance travelled for a given energy input then clearly the freewheel bike wins hands down.
(OED: “Efficiency: the ratio of the useful work performed by a machine or in a process to the total energy expended” – clearly when talking about transport modes then “useful work” can be taken to mean the total distance travelled)
Yes, I agree that’s the
Yes, I agree that’s the relevant measure of efficiency here (or, as the chart in the underlying article puts it: calories per gram per kilometer traveled). But the freewheel bike still doesn’t win. Freewheeling is a practically convenient way to adjust when you supply energy, but it doesn’t reduce the total amount of energy the system must dissipate to cover a given distance.
Indeed, at a fixed distance and fixed arrival time, coasting is actually less efficient than constant pedaling because of the aerodynamic penalty incurred when speeding up above the average speed before coasting back down below it.
Hmm… so it would equally
Hmm… so it would equally efficient not to coast down steep hills but to carefully brake and pedal? (assuming you had an appropriate gear size to keep your muscular power generation efficient – actually ensuring you stay at the “terminal velocity” you would otherwise reach by coasting due to aerodynamic drag, rolling resistence etc but also factoring in the (hopefully smallish) losses from drivetrain inefficiency and internal inefficiencies in human power generation, but accounting for the beneficial cooling effect of moving air *…).
I think that would be less efficient than coasting due to the extra mental energy expended!
* Not to be sniffed at – I believe that is a major limiting factor in human power generation over time on static cycling machines.
chrisonabike wrote:
Well, once you account for the 6×10²⁴ kg of the Earth doing the downhill work, the coasting system’s efficiency really tanks!
Hey – not fair – you won’t
Hey – not fair – you won’t count gravity (which TBF otherwise cancels – up and down) but the air resistance counts?
And suppose I never cycle uphill (granted I won’t be doing much cycling in that case…)?
Sorry, I’m not seeing this.
Sorry, I’m not seeing this. So let’s say we have completely level ground and zero windspeed with bikes of exactly the same weight and aerodynamics, one is single speed with a freewheel and one is a fixed gear of the same size. Both riders (same weight, obviously) accelerate up to 20 mph using the same cadence over the same distance. Let’s say they get to 20 mph after 200 metres and they have both expended the same amount of energy. The freewheel rider then starts coasting and travels, say, 200m farther. The fixie rider has to keep pedalling, still turning their legs even if with minimal effort, just enough not to have any resistance, to reach the same point, so they will have expended more energy to get to the same point, no?
ETA The fixie rider could of course take their feet off the pedals and just let them spin but then the energy expended by the bike in keeping the drivetrain turning would make it less efficient than the freewheel model. I see your point about efficiencies in regularity of pedalling but the fact remains that if the freewheel and the fixie rider ride a certain distance at exactly the same speed using exactly the same energy then when the fixie rider stops pedalling they stop whilst the freewheel rider who stopped pedalling at the same time coasts on, thereby travelling a greater distance for the energy expended and therefore being more efficient in terms of the energy/distance equation.
I think what they’re saying
I think what they’re saying is that the fixie rider could ride slower for the first 200m, continue pedalling for the second 200m, and arrive at the end at the same time having used less energy.
But, of course, (a) the freewheel rider could choose to do that too, and more importantly (b) people aren’t perfect machines that can accurately measure out a constant effort for the most efficient use of their energy, riding in a pan-flat world with nothing that requires slowing or stopping.
Roger that. I’m really just
Roger that. I’m really just saying that coasting is not what’s responsible for the efficiency bicycles. Indeed, coasting is less efficient than constant pedaling, scientifically speaking.
That’s only true in idealised
That’s only true in idealised circumstances, though. In the real world, where there are hills, and traffic lights, and suchlike to deal with (not to mention human variability), coasting is a large part of the efficiency of a bike. So it would be more accurate to say that coasting is not responsible for all of the efficiency of bicycles.
I agree that coasting makes
I agree that coasting makes cycling more practically convenient under a variety of real-world circumstances.
mdavidford wrote:
What part coasting contributes to a rider’s efficiency whilst cycling depends on their personal style and choices. If a rider keeps a relatively steady cadence and matches the gears to the opposing forces (drag, friction, gravity) coasting is insignificant.
Personally I find coasting to be an insignificant part my rides, but yet I still cycle much faster than I can walk or even run which demonstrates the efficiency of cycling despite not coasting.
Pub bike wrote:
Point is that in real-world circumstances this is often very difficult, if not impossible.
Sounds like you could probably be cycling a lot more efficiently then.
(Of course, you may not want to be hyper-efficient, because taking it to extremes would take all the fun out of cycling, but that’s a different conversation.)
mdavidford wrote:
Point is that in real-world circumstances this is often very difficult, if not impossible.
— Pub bikeI don’t agree. I cycle in the real world. I’ve just checked my cadence data from my last training ride and it is pretty constant and the only gaps are where I had to stop at junctions/roundabouts/slow cars. It wasn’t difficult.
I could probably be cycling a little bit more efficiently to keep a similar speed but I severly doubt I could be a lot more efficient unless I were to cycle much more slowly since power is proportional to cube of speed in fluid dynamics.
Well, taking that at face
Well, taking that at face value, I suspect you’re (a) quite lucky to have roads to ride where that’s the case, and (b) pretty atypical.
Anyhoo, this is a strong contender for Most Pointless Current Thread on Road.cc, so at this point, I’m out.
mdavidford wrote:
We apologise for the inconvenience and hope to have an even less consequential thread generating traffic (about traffic?) very soon. Can we perhaps interest you in one about the relative contributions of frame material and design vs. tyre size, design and pressure to rider comfort in the mean time?
No – but I’m very much here
No – but I’m very much here for phonetic alphabet-based banter.
mdavidford wrote:
I’m just a romeo looking for a whisky, then a tango or foxtrot.
chrisonabike wrote:
No – but I’m very much here for phonetic alphabet-based banter.
— chrisonabike I’m just a romeo looking for a whisky, then a tango or foxtrot.— mdavidford
Strictly speaking, it’s a whiskey. Although it retains the same *eaning.
(* that’s a Mike drop)
GMBasix wrote:
I prefer a more PETE-ed one myself, although that’s now considered Old-Fashioned. (And one of those wouldn’t benefit from it either).
I don’t think that’s the most
I don’t think that’s the most useful way to look at it. Instead of having an arbitrary line where both riders stop pedaling, I think it makes more sense to pick a fixed stopping point and require both riders to reach it in the same amount of time–after all, our efficiency metric is defined in terms of energy per unit of distance traveled, so let’s fix the distance traveled and set that as our target. Then we can ask whether coasting allows the freewheel rider to reach that end point in the same amount of time with less energy expended (i.e., more efficiently). And there, the answer is definitively no.
But then, even if we work from your setup, I think you’re still mistaken. When you stop pedaling on a fixed gear bike, if you truly let your legs go limp (i.e., supply no more energy), then the fixed gear bike continues moving forward almost as fast, and for almost as long, as the freewheeling bike would. Very little energy is lost to the cranks continuing to spin (and, indeed, you’re not losing any energy to the friction of the freewheel system itself). If you want to meaningfully dissipate extra forward momentum from that system (relative to the freewheel version), you would have to supply additional energy through resistance pedaling.
LookAhead wrote:
If you do that then yes, you could arrive at the same point having expended the same energy. However, if both riders expend exactly the same energy and then stop pedalling, the freewheel rider goes farther and therefore spends less energy per unit of distance travelled. Even if you set a fixed distance, if both riders ride at exactly the same pace with the same cadence using the same sized gear there will always be a point before the line at which the free wheel rider can stop pedalling and coast whilst the fixie rider will have to keep turning their legs, even if they are not actually exerting any force on the pedals, in which case they will use more energy to reach the line.
If your legs are genuinely not putting in any energy whatsoever but are still on the pedals then a considerable amount of energy is being expended by the drive chain in pushing your legs up and down. If you want to have zero impedance from your legs you either have to take them off the pedals completely or expend a certain amount of energy in keeping them moving to ensure there is no resistance against the pedals. You could, as I said, take your feet off the pedals and just let them spin but I’m pretty sure (although I admit I am now in the realms of intuition) that the impedance of keeping the chain turning and the pedals spinning would be greater than that provided by a freewheel.
I think it might help if we
I think it might help if we first see where (if anywhere!) we agree. Are we in agreement that, contra road.cc’s claim, coasting is not primarily what’s responsible for making cycling more efficient than walking?
LookAhead wrote:
Yes, definitely agree on that!
Ah, cool! So then a couple of
Ah, cool! So then a couple of things.
If the distance and the time to cover the distance are held constant, then constant pedaling is more efficient than pedaling and coasting, as explained above.
If time is not held constant, then I think constant pedaling still wins. In order to make use of coasting, the freewheel rider is going to have to pick up enough speed (read: greatly increase his aerodynamic drag and the energy required to overcome it) so that at some point he can stop inputting more energy and continue to coast until friction and drag dissipate all of that already supplied energy just as he crosses the finish line. Meanwhile, the constant pedaler can just maintain an ultra low speed the whole time, minimizing his drag, and cross the finish line having used less energy than the freewheel rider (because the extra energy he used in order to pedal across the finish line is outweighed by the energy he saved due to steadily low aerodynamic drag).
If distance is not held constant–if both riders ride at the same speed and stop pedaling at the same time–then I think the freewheel rider finally wins, but just by a little. The freewheel rider immediately saves all losses from drivetrain friction and only has to add a small loss from freewheel friction. The fixed gear rider still has losses from the spinning bottom bracket and chain, plus just a bit more from the internal friction of his limp legs (it’s not true as you say that “then a considerable amount of energy is being expended by the drive chain in pushing your legs up and down”–what has been pushed up gets to fall down). The fixed gear rider stops slightly short, as his drivetrain + leg damping losses are a bit greater than the freewheeler’s freewheel losses.
Sorry, still don’t agree. In
Sorry, still don’t agree. In the simplest possible terms, if you have your “constant pedaller” on the fixed gear and the rider with the freewheel exactly mimics them in terms of power output, at some point before the finish line the freewheel rider can stop putting in energy and freewheel to the line while the fixed gear rider will have to carry on pedalling because if they don’t they will stop. Let’s say the two of them are doing one lap of a 200 metre track, even at your ultra low speed. If they both ride round the track at 10 km/h they will use exactly the same energy until they get, say, 20 m from the line when the freewheel rider stops pedalling and freewheels over the line while the fixed gear rider still has to expend energy keeping their legs moving to the end. Therefore the freewheel rider has used the same energy as their counterpart for 90% of the distance and then none for 10%, whereas the fixed gear rider has used that same level of energy for 100% of the distance, ergo for distance covered versus energy expended the freewheel rider is 10% more efficient.
Rendel Harris wrote:
They don’t need to ride around the track at the same speed. The fixed gear rider can ride arbitrarily slowly and reduce his aerodynamic drag almost to zero. By contrast, if the freewheel rider were to ride that slowly, he wouldn’t have sufficient kinetic energy in the system to overcome friction losses and continue forward motion when he finally stopped pedaling. Therefore, at some point he’s going to have to speed up to build enough kinetic energy to coast to the line, and that’s where the energy he expends to overcome aerodynamic drag outweighs the energy expended by the fixed gear rider to pedal (just) over the line.
I think you’re getting into
I think you’re getting into the realms of the theoretical there, for a rider to be going so slowly that there would be absolutely zero forward movement immediately they stopped pedalling due to friction/aerodynamic resistance they would have to be travelling at…well I don’t know how to work that out but we can safely assume I think that it would be in the order of hundredths of kilometres per hour, a speed at which both riders would doubtless have long ago have fallen off. Anyway, I think we’re starting to go round in more circles than our theoretical riders here so we’ll agree to disagree shall we – thanks for the chat!
I have to admit I was getting
I have to admit I was getting a little worried about the extra energy my fixed gear rider would have to expend to stay upright!
I was ready to put him on a tricycle if pushed?
LookAhead wrote:
Well obviously if you’re having him pushed that’s just cheating…
Rendel Harris wrote:
I think he just said that for balance
Rendel Harris wrote:
The cranks just spinning are effectively a funny shaped flywheel so there will be a slight aerodynamic penalty but probably very similar to the resistance of the freewheel, you don’t get that clicking sound for free!
Rendel Harris wrote:
Setting the uphill/downhill thing aside for a moment, on the flat, at the same cadence and the same gear, the fixed-gear rider will be exerting less power than the freewheel rider. The freewheel rider will have to expend a touch of energy to turn the pedals through TDC/BDC where the fixed-gear rider can just let the momentum of the drive-train do it for them. (This sometimes catches me out when I switch back to a freewheel bike after a period on fixed – I’ll ‘stutter’ my legs at TDC/BDC and the crank stalls, very weird; have to remember to keep pushing the pedals through on a freewheel).
Further, if by freewheel you mean freewheel + rear derailleur (not just a single-speed), then there is an additional cost the freewheel+rd rider is paying: The jockey wheels and their friction, plus the additional chain friction of the multiple additional bends. This is definitely non-negligible, as every fixed-gear rider will attest to. It’s at least a few watts, even compared to a really efficient road bike. And perhaps 5W or more compared to a typical, not-100%-pristine RD drivetrain.
As for downhills, it depends on the downhills. For shortish uphills and downhills, I think the fixed-gear could still be more efficient, just cause of the momentum benefits you get from the less draggy drive-train.
Paul J wrote:
For the record I did mention somewhere in the morass below that I was talking about comparing a single speed freewheel bike and a fixed gear bike in this instance. I am fully appreciative of the efficiency gains that can be made by eliminating the rear mech!
The idiocy of mankind tells
The idiocy of mankind tells us that governments miss the obvious.The UK had a pledge to remive ICE by 2030,. Yet this could have been better approached by incentivising an audit trailed bike to work replacement for ICE owners. Ebikes too.
I am also sure there would me willing volunteers assisting new bikers with finding both safer routes and fairly low tech audits. Some do care !
World inefficiency is the norm, that now going hyper inefficient over in the US.
I can hardly walk at the
I can hardly walk at the moment, but I can travel about 5 times faster on my bike.
I find this information a
I find this information a little dangerous (as a little information often is). The car and the human have the same energy output when accounting for weight, so you could infer that driving is as efficient as walking, so why should I walk anywhere when I can drive?
However I would suggest that this efficiency includes weight of the car and passenger. If considered in terms of cargo weight it would be different.
Walking isn’t very efficient
Walking isn’t very efficient but because humans weigh very little relative to cars they use much less energy to propel themselves, and it isn’t much more energy than a human uses just keeping alive.
Cars use very little energy to run per kilo*, but they weigh 10-30x more than the humans they carry so they use a lot more energy to propel themselves relative to walking. Cars are especially wasteful when the occupancy is low.
Bicycles on the other hand are very light – much lighter than a human – and a human on a bike expends very little energy to propel themselves so relative to cars they are extremely efficient.
A more useful chart would expressed in terms of energy consumed per passenger metre and not vehicle weight but that was not the purpose of the study.
* not sure why the study used grammes when it is not the base SI unit. Should have been kilos.
Well, on the basis of this
Well, on the basis of this comments section, cycling is no longer the most efficient mode of travel. It has converted a lot of energy to displaced heat BTL here!
The graphs need updating.
The graphs need updating.
None of them shows the beer scooter, surely the most efficient mode of all; it just… happens.
nothing like stating the
nothing like stating the obvious.
I hate to beat a dead horse,
I hate to beat a dead horse, but this is still badly wrong and road.cc should correct it:
“Much of the efficiency stems from the coasting along that the wheels enable. Where walking requires a constant expenditure of energy, cycling on flat terrain does not require constant pedalling.”
I’m not sure what bringing in
I’m not sure what bringing in the efficiency of dead horses would add to the article.
Well, if the dead horse were
Well, if the dead horse were to find itself at the top of a slippery slope…