Every post on this blog is so impressive! Love it!

Beautiful article.There&#x27;s a similar neat video, &quot;Most People Don&#x27;t Know How Bikes Work&quot;, where they fix the steering so the handlebars can only be turned left, and people then aren&#x27;t able to turn left.<a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac</a>

Great, this is the best way start the day!

Go tubeless!<a href="https:&#x2F;&#x2F;youtu.be&#x2F;skW_Ysew3zw" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;skW_Ysew3zw</a>

Dang, you beat me to it, I was busy inflating my tires to 120 psi.

You probably know this...but the song is not about a literal bicycle...it&#x27;s about Freddie being &quot;bi&quot;. I only say this because it took me too long to realize that.

Other soundtrack option: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=HLUX0y4EptA">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=HLUX0y4EptA</a>

Pshh, I know how to ride a bicycle, why is ciechanowski writing an article about riding a bicycle?!Holy moly!! I didn&#x27;t realize I didn&#x27;t know how I actually ride a bicycle!!Obligatory sound track for this excellent post:<a href="https:&#x2F;&#x2F;youtu.be&#x2F;KwvWtZl2ICY" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;KwvWtZl2ICY</a>

Worth watching but for folks who want a TL;DW:<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering</a>

Veritasium is some low quality trash, next.

It&#x27;s actually linked deep in the article.

You will love the interesting video, &quot;Most People Don&#x27;t Know How Bikes Work&quot; by Veritasium - <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac</a>

Another instant classic from Bartosz Ciechanowski!

This is such a well made explanation! Tons to learn from this. Good job!

This is the greatest explanation of two-wheeled vehicle dynamics I&#x27;ve ever seen. Anyone who rides a bicycle or motorcycle should read this whole thing!

&gt; This does not make sense to me. If the two forces are truly of equal magnitude, then shouldn&#x27;t the one that is in-line with the center of mass accelerate it faster, since 100% of the force is being converted to linear momentum, while the off-center force is being split between increasing linear momentum and rotational momentum?Forces don&#x27;t &quot;split&quot; that way. 100% of the force goes into creating linear acceleration, and 100% of the force goes into creating torque.&gt; This would appear to violate the conservation of energy.It&#x27;s not. The off-center force does more work, putting more energy into rotation.

This makes sense, thank you.I think in my head I was mixing up &quot;force&quot; and &quot;power&quot;; it&#x27;s clear that with two cubes travelling linearly at the same velocity, the one that&#x27;s also rapidly spinning has more energy.That it can take varying amounts of energy to apply the same amount of force to the same object was the missing piece for me, since I was thinking of force as power.

Lots to unpack here.First, there is no splitting between linear momentum and angular momentum per se. They have different units, you can&#x27;t add them, and it makes no sense to say &quot;this is 30% linear momentum and 70% angular momentum&quot;. But you can calculate how much energy is stored in linear motion and how much is stored in angular motion, and (at least at non-relativistic speeds), you can indeed add them. So you are on to something here.But Newton&#x27;s Laws don&#x27;t lie. If you apply a force F, then a=m&#x2F;F, and the fact that the object is spinning doesn&#x27;t change the acceleration. Yet applying the force off-center does indeed seem to add more energy to the object: you&#x27;re accelerating it just as much as if you applied the force on-center and you&#x27;re also spinning it.So how do you resolve this? A piece of general advice in physics (and math, and many other fields) is to state your assumptions and your questions precisely and unambiguously. The question is: if you apply an equal force to two objects of equal mass, and there are no other external forces involved, how can one accelerate faster? But just because the forces are equal doesn&#x27;t mean that the work (energy applied) is the same. In fact:W (work) = F (force) * d (distance)Divide by a small unit of time:P (power, which is work per unit time) = F * v (velocity, which is distance per unit time)And that&#x27;s the velocity of the point that receives the force. And if you look at the animation, you will see that the off-center force on the rotating box is applied to a (variable) spot on the box that is moving to the right. So the power needed to apply the force is larger, and more work is done.(In fact, the excess velocity is ωr, so the excess power is Fωr = ωτ (angular velocity times torque), which is exactly the power needed to produce angular acceleration. So energy is conserved and all is well.)

Thank you for asking this question! I had a similar confusion in the past, and I had never really worked it out until I saw amluto&#x27;s answer now!

&gt; The further away that line is from the center of mass, the easier it is for the force to rotate the object. In the following demonstration, you can apply two forces of the same magnitude to two identical boxes. The only difference is the distance to the center of mass at which these forces act:&gt; When the distance between the force-line and the center of mass is large, the box spins faster as well. That distance doesn’t change the acceleration of the box to the right and both boxes move with the same linear speed. However, that distance affects the angular acceleration of a box – the longer that arm, the faster the box spins.This does not make sense to me. If the two forces are truly of equal magnitude, then shouldn&#x27;t the one that is in-line with the center of mass accelerate it faster, since 100% of the force is being converted to linear momentum, while the off-center force is being split between increasing linear momentum and rotational momentum?This would appear to violate the conservation of energy.

Same here. What an amazing content he makes.

Right? His posts are an equivalent of new GTA releases when I was a kid.

i&#x27;m a simple man: i see ciechanow.ski, i press &quot;like&quot;

<a href="https:&#x2F;&#x2F;ciechanow.ski&#x2F;mechanical-watch&#x2F;" rel="nofollow">https:&#x2F;&#x2F;ciechanow.ski&#x2F;mechanical-watch&#x2F;</a> this is still my all time favorite blog post.

I saw the domain name &quot;ciechanow.ski&quot; and immediately upvoted it even before I opened it. The quality of posts by Bartosz is just next level.

Also see the work of Jason Moore (referenced in that blog) for whom it seems modeling bicycle dynamics in open source scientific python has been a huge passion for him for more than ten years. I remember in the scientific python development in those days there were these guys from like the hubble optics correction division and like the asml metrology department and then this one weird bicycle guy lol.<a href="https:&#x2F;&#x2F;moorepants.github.io&#x2F;dissertation&#x2F;" rel="nofollow">https:&#x2F;&#x2F;moorepants.github.io&#x2F;dissertation&#x2F;</a><a href="https:&#x2F;&#x2F;github.com&#x2F;moorepants">https:&#x2F;&#x2F;github.com&#x2F;moorepants</a>

&gt; As in, you only counter steer a motorcycle above ~10mphI don’t believe that this is true. Can you explain the physics?

Countersteering applies at all speeds, it&#x27;s just that balance plays a bigger role at lower speeds.  The wikipedia article on countersteering goes into this a little bit.

This effect has a big play on motorcycles.  Riding a bicycle is considered prerequisite knowledge for learning to ride a motorcycle, largely because of this counter steering. One thing that is more pronounced on a motorcycle is that counter  steering only occurs while the bike is moving at speed.  As in, you only counter steer a motorcycle above ~10mph (higher for some motorcycles). It&#x27;s really cool to think about how intuitive this switch is, almost everyone picks it up quickly and it becomes second nature.

Veritasium did a video where they stopped him from counter-steering and couldn&#x27;t steer anymore. <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac</a>He might be wrong, and just didn&#x27;t know enough, but he is usually researching his videos very well and I would be surprised for him to be wrong about this.

I&#x27;m not sure your line method proves much since the countersteer could be very subtle. However I think you&#x27;re still right. Countersteer makes you start to fall faster, but it clearly isn&#x27;t necessary to make you fall because you do that anyway!Next time I&#x27;m on my bike I will try it anyway.

No it&#x27;s not necessary in the strictest sense of the word, but counter steering achieves higher turn speeds, offers better control and precision, requires far less physical effort, and works at nearly every speed. I can&#x27;t think of many pragmatic reasons not to use counter steering outside of just screwing around for fun.

Countersteering is convenient, but not required. A bicycle and rider are not a single rigid body. You can simply lean to one side and you&#x27;ll have to steer in that direction to keep your bike under you -- no countersteer necessary.I am not saying people don&#x27;t countersteer, only that it isn&#x27;t necessary to make a turn.Also, bicycles aren&#x27;t motorcycles where the weight ratio between rider and vehicle is swapped.If you don&#x27;t feel like clamping your handlebars so they only turn one direction, try this: coast along a straight line (and outdoor basketball court is great). Then pick a direction and just lean that way. You can absolutely keep your wheels on the line until you turn in the direction you picked, with no countersteering necessary.This &quot;fact&quot; came about with a video of low skill riders who can&#x27;t manipulate a bike very well, or don&#x27;t know what it is they&#x27;re doing when they do it.

I&#x27;ve always loved that little fact about having to initially turn the handlebars the opposite way to initiate a turn.It&#x27;s pretty much impossible to believe without thinking it through, and yet everyone naturally intuits it.It&#x27;s one of my favourite examples of how the brain can just &#x27;feel&#x27; forces and make the right adjustments incredibly fast. So amazing.

Wait until (all) teachers start using AND SHARING really well crafted prompts for teaching aides &#x2F;r&#x2F;coolguides lesson material.There should be a central repo for all subjects where topics can be looked up to find a guide like this one - and the prompt is public, with revision edit logs (like wikipedia) such that a standard agreed upon response can be adopted by acedmia for explaining a particle concept.Let the acedemics expand upon, tangent from, deep dive into the sub components of each topic.The University.ai

Another great interactive explanation.I wish physics teachers start using geometric product of vectors, instead of the cross product. This allows forces and torques to be combined into a single concept &quot;Forque&quot;. Really, translations are just rotations around infinity and rotations are just composition of two reflections. If we allow the algebra to take care of rotations, physics becomes a lot simpler.

A much worse book on the science of bicycles is &quot;The Third Policeman&quot; from Flann O&#x27;Brien.Some of its wisdom:<pre><code> “The gross and net result of it is that people who spent most of their natural lives riding iron bicycles over the rocky roadsteads of this parish get their personalities mixed up with the personalities of their bicycle as a result of the interchanging of the atoms of each of them and you would be surprised at the number of people in these parts who are nearly half people and half bicycles...when a man lets things go so far that he is more than half a bicycle, you will not see him so much because he spends a lot of his time leaning with one elbow on walls or standing propped by one foot at kerbstones.”</code></pre>

Link to the book directly from MIT Press: <a href="https:&#x2F;&#x2F;mitpress.mit.edu&#x2F;9780262538404&#x2F;bicycling-science&#x2F;" rel="nofollow">https:&#x2F;&#x2F;mitpress.mit.edu&#x2F;9780262538404&#x2F;bicycling-science&#x2F;</a>

A great book on the science of bicycles is &quot;Bicycling Science&quot; from MIT press. <a href="https:&#x2F;&#x2F;www.amazon.com&#x2F;Bicycling-Science-Press-Gordon-Wilson&#x2F;dp&#x2F;0262538407&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.amazon.com&#x2F;Bicycling-Science-Press-Gordon-Wilson...</a>

I see new post from Bartosz, I upvote. Simple as that.

Ball-bearings? Primitive?? Surely you jest!

Agreed. Bicycles are kind of a miracle of seeming simplicity hiding a ton of important developments of the industrial age. 99 Percent Invisible did a recent episode on just this topic: <a href="https:&#x2F;&#x2F;99percentinvisible.org&#x2F;episode&#x2F;the-safety-bicycle&#x2F;" rel="nofollow">https:&#x2F;&#x2F;99percentinvisible.org&#x2F;episode&#x2F;the-safety-bicycle&#x2F;</a>.

Yep, 90% materials, and so are other things like windsurfing, paragliding, etc.Very little of the &quot;modern stuff the ancients didn&#x27;t figure out&quot; could be done without modern materials.If dumped back in time, maybe you could make rent teaching swimming or doing accounting. Medicine would probably be too dangerous.

To expand on one of those things - bike chains get slightly longer as they wear out. Once it&#x27;s about 1% longer than it started, it looks about the same as it always did, but it&#x27;s starting to damage the drivechain and you need to replace it. An ancient Roman blacksmith has no hope of making a chain with anything like that level of precision.

The key invention that made them possible was ball bearings. This is why the modern bicycle and the modern car were invented within a year or two of each other.

&gt; Bikes benefit a lot from […] smooth asphalt (not cobbles)Bicycle riding societies were some of the more vocal proponents on paved roads (predating the automobile):* <a href="https:&#x2F;&#x2F;www.vox.com&#x2F;2015&#x2F;3&#x2F;19&#x2F;8253035&#x2F;roads-cyclists-cars-history" rel="nofollow">https:&#x2F;&#x2F;www.vox.com&#x2F;2015&#x2F;3&#x2F;19&#x2F;8253035&#x2F;roads-cyclists-cars-hi...</a>* <a href="https:&#x2F;&#x2F;www.theguardian.com&#x2F;environment&#x2F;bike-blog&#x2F;2011&#x2F;aug&#x2F;15&#x2F;cyclists-paved-way-for-roads" rel="nofollow">https:&#x2F;&#x2F;www.theguardian.com&#x2F;environment&#x2F;bike-blog&#x2F;2011&#x2F;aug&#x2F;1...</a>* <a href="https:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;travel&#x2F;american-drivers-thank-bicyclists-180960399&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;travel&#x2F;american-drivers-thank...</a>

Well, I&#x27;ve got a bike from the 30s and it&#x27;s perfectly fine for everyday riding. While I agree that most of those things you listed are valuable and convenient, good enough is often just good enough. Like I&#x27;ve got no use for any cables and I don&#x27;t need precision engineered chains.

Bikes benefit a lot from pneumatic tyres, pressure pumps, smooth asphalt (not cobbles), precision engineering of chains, chemistry of oils and lubricants, rust-proof steel, rubber brake pads with compounds that last long enough and resist rain, spring steel for suspension, cables that don&#x27;t stretch. Without those things you get a wooden boneshaker hobby-horse, large, heavy, energy inefficient, incovenient: <a href="https:&#x2F;&#x2F;duckduckgo.com&#x2F;?q=hobby+horse+victorian+bike&amp;t=ffab&amp;iar=images&amp;iax=images&amp;ia=images" rel="nofollow">https:&#x2F;&#x2F;duckduckgo.com&#x2F;?q=hobby+horse+victorian+bike&amp;t=ffab&amp;...</a>(And internal combustion engines; how are you going to distribute them around the Roman Empire by the tens of millions without trucks or ships?)

Don&#x27;t even get me started on airplanes though - there was only 66 years between the first airplane (Wright Flyer in 1903) and the moon landing (1969).Disclaimer: that&#x27;s of course a cool anecdote on the surface, but rockets have been around since the 13th century so they&#x27;re two mostly different technologies.

You will be amazed to know that the Ball Brothers, who invested the Mason Jar&#x2F;Atlas Jar, and perfected canning and soups... is also Ball Aerospace - who makes super-high end space components for the MIC, black projects, skunkworks, NASA etc...All from the Mason Jar.<a href="https:&#x2F;&#x2F;www.visitmuncie.org&#x2F;a-legacy-etched-in-glass-the-ball-brothers-in-muncie&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.visitmuncie.org&#x2F;a-legacy-etched-in-glass-the-bal...</a>(also &quot;Aliens&quot;)

I guess perspective makes it a lot less surprising that the first airplanes were made by bicycle manufacturers.

It takes a LOT more calories to power a horse than a biker.

A thought:The invention of the bicycle came at a similar time like engine driven vehicles. Before those became popular, the direct competitor for bicycles (one person transportation) were horses.There might have literally not been a need to invent a bicycle as horses fulfilled the same purpose and had the advantage that they fared better on the back then nearly non-existent infrastructure.Also: a single person transportation vehicle was not something a lot of people needed in their lives. You needed something to move stuff, but the demand to move single people daily came into existence with the dawn of big cities.

A parallel thought is that the first airplane is the product of bicycle mechanics and not railway or automotive mechanics.
As others pointed out, there are a lot of necessary technologies like rubber, bearings, lubricants, sprockets and chains that need to be developed, but there is also something very elegant about bicycles. If you start to mess around with a 70&#x27;s era road bikes you get a sense of just how perfectly everything needs to fit together and how everything affects everything else. (You see it more clearly in older bikes because you need to deal with non-standard parts). I think I learned more about bicycles from the royal pain of a 1982 Peugeot than anything else. This is not to say that a car doesn&#x27;t have similar complexity, but the use of chemical fuel and 4 wheels masks how the tunings fit together. With my current bike there is a serious difference when it is perfectly tuned.

They could&#x27;ve just made them out of carbon fiber composites before &#x2F;s

The production of quality steel isnt thousands of years old.Yeah they could produce small items - but to make the steel of the quality needed for bicycles is pretty new - the past 150-200 years with the Bessemer process

The modern &quot;fat bike&quot; would be (is!) quite good at traversing a variety of natural terrains where humans live, without roads or paths&#x2F;trails.

Mountain bikes do not require roads or flat paths; they work fine on trails (hence the name &quot;mountain bike&quot;), which have existed since large animals evolved.However, mountain bikes arguably require even more technologies than other bicycles, especially for suspension and brakes (MTBs pioneered the use of disc brakes on bicycles).

Bicycles are a relatively new invention because they require roads&#x2F;flat paths which are also a relatively new occurance, and came about due to the widepread use of horses and then carraiges for transportation.A bike at any other point in human history would have been completely useless trying to traverse natural terrain.

I always loved the scene in HBO&#x27;s Deadwood when the first bicycle comes to town and everyone gathers to watch someone try and ride it.

No shit, you can make an airplane if you know your way around a bicycle as the wright brothers demonstrated. They were bicycle mechanics originally.

The safety bicycle (chain, pedals in the middle) is about a decade newer than the car (under 150 years), although they hit mass production within a year either side of each other depending in how you define it.

&gt; Bikes seem like such a primitive technology, and yet as this article demonstrates, it takes a lot of engineering to design even primitive products.Very strange. I get that we take things for granted if they&#x27;ve been around forever (ie. since before we were born). But I never considered bicycles &quot;primitive&quot;. What makes you think that? Is it because they don&#x27;t need electronics? What is a non-primitive transport technology?

The timing of the invention of the bike is discussed here: <a href="https:&#x2F;&#x2F;rootsofprogress.org&#x2F;why-did-we-wait-so-long-for-the-bicycle" rel="nofollow">https:&#x2F;&#x2F;rootsofprogress.org&#x2F;why-did-we-wait-so-long-for-the-...</a>He settles on general economic and cultural factors. Experimentation requires there to be enough people with spare time and resources to play around with things with no immediately obvious payback.

I always find it interesting to think about bicycles and just how recently they were invented.Compare bicycles with steel making, for example. Steel making happened thousands of years ago. The modern bicycle was what - under 200 years ago?Bikes seem like such a primitive technology, and yet as this article demonstrates, it takes a lot of engineering to design even primitive products.It makes me wonder how many other simple or primitive products are out there which have yet to be discovered.

At equal diet, the bicycle always win. You don&#x27;t eat significantly more meat because you are using a bicycle to move vs a total couch potato that would use a Prius and eat the same.

if anything this is an argument against the paleo diet and nothing else...

This is definitely the kind of generic tangent &#x2F; screed I believe to be discouraged here.

Perhaps more carbon efficient, but 15x less energy efficient:&gt; Biking takes around 25 kcal&#x2F;km [iii] above basal metabolism, which is equivalent to .11 MJ&#x2F;km. A typical car in the US gets 25 mpg, or 9.5L&#x2F;100 km, which is equivalent to 3.3 MJ&#x2F;km. The Toyota Prius takes only 5 L&#x2F;100km, or 1.7 MJ&#x2F;km. So a typical car takes 30x more energy per kilometer than biking, and a Prius takes 15x more. This is what we expect given how much heavier cars are than bikes.

Not even close to true. I can ride 60-70 miles on reasonably hilly terrain on about 2000kcal. There’s no car that can come close to that. And that’s assuming drivers don’t eat (the McDonald’s wrappers I see by the side of the road proves that they do).

But the cyclist is doing his required weekly activity.     
The prius occupants will have to do sport on the side to stay healthy ...

&gt; They are the most energy efficient form of transportation.If the cyclist is vegan or even an average diet, yes. If the cyclist is paleo, a Prius with 2-person occupancy may actually be more carbon-efficient:<a href="https:&#x2F;&#x2F;keith.seas.harvard.edu&#x2F;blog&#x2F;climate-impacts-biking-vs-driving" rel="nofollow">https:&#x2F;&#x2F;keith.seas.harvard.edu&#x2F;blog&#x2F;climate-impacts-biking-v...</a>

Not any natural environment or terrain.Modern fat bikes will be more efficient than walking in the scrub desert where I live, in grasslands, in not too dense woodlands, on any kind of open dirt&#x2F;sand.

The rest of the world disagrees with that assertion.<a href="https:&#x2F;&#x2F;worldbicyclerelief.org" rel="nofollow">https:&#x2F;&#x2F;worldbicyclerelief.org</a>

They don&#x27;t require a flat and smooth surface, but do benefit from a road of some sort. How do you make a road? You ride on it over and over again. Ever seen a sheep track? Is that not natural?A smooth and flat road, while not necessary, is better and does make things a lot more efficient. The same is true for any wheeled vehicle but cyclists appreciate it a lot more than motorists.

&gt;They are the most energy efficient form of transportation....On flat smooth surfaces. On any natural environment or terrain they are nowhere near as efficient as walking.

They are the pinnacle of personal transportation technology. Not aware of anything that comes close. I&#x27;m not sure how anyone can use a car, keep filling it with more and more fossil fuel and think &quot;yeah, this is good technology&quot;.

Bicycles are truly beautiful machines. They are the most energy efficient form of transportation. You can travel pretty long distances with not that many calories.

I&#x27;m using Firefox on a mid-range Android phone and it seems to behave fine. Maybe  reboot your computer and see if the site is less laggy?

ciechanow.ski pages are usually super performant for me, but this one is super laggy, especially widgets with the bicycle man&#x2F;mesh. Anyone else experiencing this?

This is a really impressive article -- he went quite far into the physics of bikes and wheels and didn&#x27;t say anything that I could point to as being wrong.

Fantastic for teaching high school physics

If you don’t know Bartosz Ciechanowski‘s site yet, checkout his archives.Be careful if you have deadlines for today though, you may be there for a long and awesome time.

Nice demo of countersteering. When you jerk the slider quickly to the right, you can see that the right handlebar briefly lunges forward (left steer) before the steering recovers to the right. It&#x27;s still noticeable with smaller&#x2F;slower movements of the slider, but not as much.

Somewhat related:How many neurons does it take to ride a bycicle?<a href="https:&#x2F;&#x2F;paradise.caltech.edu&#x2F;~cook&#x2F;papers&#x2F;TwoNeurons.pdf" rel="nofollow">https:&#x2F;&#x2F;paradise.caltech.edu&#x2F;~cook&#x2F;papers&#x2F;TwoNeurons.pdf</a>

Bartosz is the quality bar I aspire to when I write my blog posts. I&#x27;ve always added interactivity in mine, but they in no way approach the detail and polish that he puts into them.

Awesome stuff as always. Don&#x27;t forget to support his patreon: <a href="https:&#x2F;&#x2F;www.patreon.com&#x2F;ciechanowski" rel="nofollow">https:&#x2F;&#x2F;www.patreon.com&#x2F;ciechanowski</a>

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.

The idea is older:<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Human-powered_aircraft" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Human-powered_aircraft</a>

If we take distance passed as a measurement, intuition tells me that bicycle is more efficient, since it doesn&#x27;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.

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 &quot;the perfect transducer to match man&#x27;s metabolic energy to the impedance of locomotion&quot;.[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.

&gt; I vaguely recall that people did state that rowing is what you should use to get the most energy out of a human bodyThe 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&#x27;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&#x27;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&#x27;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!

&gt; the source cited for it being the most efficent self-powered means of transportation is from March 1973what was the source please? ive actually tried to track this down for the steve jobs quote but couldnt find it

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&#x27;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&#x27;s one from 10 years ago, and it just so happens that I had made my account by then so this was probably it: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=6028326" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=6028326</a>

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.

I hope you&#x27;re not implying that people in countries with hills don&#x27;t use a bicycle because that&#x27;s not true ;-) Check Denmark and Sweden for instance.

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

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

I wouldn&#x27;t say it&#x27;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&#x27;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&#x27;s a much bigger engineering challenge than making a simple paddle and a boat that floats with no holes in the bottom.

It&#x27;s no coincidence that other human-powered transport mechanisms (aircraft, boats, etc.) commonly use pedals for the drivetrain. It&#x27;s a lightweight way to use the body&#x27;s strongest muscles, especially when high power is critical.See:<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MacCready_Gossamer_Condor" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MacCready_Gossamer_Condor</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MacCready_Gossamer_Albatross" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MacCready_Gossamer_Albatross</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MIT_Daedalus" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;MIT_Daedalus</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;AeroVelo_Atlas" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;AeroVelo_Atlas</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Hydrocycle" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Hydrocycle</a>

And, in the very very long term 200yrs+, it&#x27;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 &quot;normal&quot; 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).

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.<a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=ob_GX50Za6c">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=ob_GX50Za6c</a>

&quot;studied&quot; 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

Steve Jobs studied movement efficiency, and that’s was why he called the Macintosh a “bicycle for the mind”<a href="https:&#x2F;&#x2F;www.themarginalian.org&#x2F;2011&#x2F;12&#x2F;21&#x2F;steve-jobs-bicycle-for-the-mind-1990&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.themarginalian.org&#x2F;2011&#x2F;12&#x2F;21&#x2F;steve-jobs-bicycle...</a>

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.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bicycle_performance" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bicycle_performance</a>

All the posts on ciechanow.ski are mind-blowing. The graphics, the gradual process of explaining from simple fundamental concepts to the complete picture.How I wish our schools would teach like this.

electric bikes have quietly revolutionized nyc delivery, with food deliveries now going halfway across manhattan and between boroughs, no big deal.

Great articles, no ads, except this one:Voluntary contribution of $3 or more per article, via Patreon: <a href="https:&#x2F;&#x2F;www.patreon.com&#x2F;ciechanowski" rel="nofollow">https:&#x2F;&#x2F;www.patreon.com&#x2F;ciechanowski</a>(Not sure what &quot;per article&quot; means though. How to donate for past articles? Will I get billed whenever a new article drops?)

I’m not even done with reading, but i’ve been very interested in bikes and how they work for quite some time now and I can confidentially say that this is on of the best writeups there is.
Thanks to the author for making this

I&#x27;ve loved every article he&#x27;s done so far. He only publishes about once a quarter and usually his articles are ~2 hours long. I&#x27;ve yet to be unimpressed.

If you don’t have time to read it, why do you have time to comment on it?

Wow. Beautiful piece of art, but I am not going to read it. For someone who has, is the length of the article proportional to the gained knowledge, or could that be expressed much more succinct?

Great.  My complaint about the animation stands.

Countersteering is explained later in the article.

The first animation is sort of wrong. To turn right on a bicycle, you actually steer slightly left (and vice versa). It&#x27;s very jarring to see the wheel rotated in the same direction of the turn at extreme lean angles -- if you do that in the real world, you&#x27;ll crash.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering</a>

Custom webgl, I believe. You can check the page source.

That would be something I&#x27;d personally consider out-of-date with modern chains. Apparently that makes me a &quot;Lazy, careless cyclist&quot; as I would never use grease on a chain. Nor would I ever follow this insane method of cleaning a chain.Guess I&#x27;d consider myself to be an efficient cyclist, which may be construed as &quot;lazy&quot; by some.edit: reading onward, he claims &quot;Serious cyclists, who value performance..&quot;. I wonder what he considers &quot;performance&quot;, because it sure appears he didn&#x27;t consider or measure drivetrain efficiency.

Sheldon Brown is a great resource for bike information - lots of no-nonsense advice and explanations though it is getting a bit out-of-date now since his death. A particular favourite of mine is his chain cleaning method: <a href="https:&#x2F;&#x2F;www.sheldonbrown.com&#x2F;chainclean.html" rel="nofollow">https:&#x2F;&#x2F;www.sheldonbrown.com&#x2F;chainclean.html</a>

Also worth mentioning bicycle related is the lifework of Sheldon Brown: <a href="https:&#x2F;&#x2F;www.sheldonbrown.com" rel="nofollow">https:&#x2F;&#x2F;www.sheldonbrown.com</a>Not fancy looking, but very interesting.

&gt; Since our planet is very heavy, the acceleration of the Earth and the wall attached to it is effectively non-existent.If the applied force is anchored to the ground too, if doesn&#x27;t matter how heavy the planet is.

Try just leaning before steering.  Countersteering is not required.

Beautifully illustrated and brilliantly explained.Derek Muller (Veritasium) on YouTube has a related video diving into the mechanics of bicycle riding. It shows what happens if you prevent the rider from performing the countersteer before leaning into a turn [1].[1]: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;9cNmUNHSBac" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;9cNmUNHSBac</a>

&gt;&gt; Once mastered, the simple action of pedaling to move forward and turning the handlebars to steer makes bike riding an effortless activity.Except you don&#x27;t really turn the handlebars to steer, movement is far more than just pedaling and it&#x27;s never an effortless activity if done right. Everything else in this sentence is correct though ;)

And its counterpart quote by Bill Gates, &quot;Bicycles are like a computer for our legs.&quot;

Immediately made me think of Steve Jobs and this great clip:&quot;Computers are like a bicycle for our minds.&quot; <a href="https:&#x2F;&#x2F;youtu.be&#x2F;ob_GX50Za6c" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;ob_GX50Za6c</a>

Common mistake: you are confusing energy and momentum, or power (rate of energy&#x2F;work) and force (rate of momentum change). In fact, power at constant force is F.v (force time velocity), which solves your question.

If you don’t shift gears, then your pedals increase in speed as your bike accelerates. So your power consumption goes up with speed even though force is constant.

Work (change in energy) is F*d, so the force you&#x27;re applying to go from 10-&gt;20m&#x2F;s happens over a larger distance if it&#x27;s the same force.

Hmm.. the acceleration part.E=(mv^2)&#x2F;2 - so we put more energy accelerating the bike from 10-20m&#x2F;s than 0-10m&#x2F;s, no?Yet a=F&#x2F;m - which suggests the acceleration is proportional to force, which would suggest that applying force F for time t should speed you up 0-10m&#x2F;s the same way as 10-20m&#x2F;s?I suspect the force applied to the pedals is not the force which is acting on the bike (counter-force of the ground-bike system) and this second force is somehow relatable to the current speed of the bike, no?

I&#x27;ve never built or adjusted a wheel. My understanding its not for the faint of heart. The late husband of one my CS professors (Sheldon Brown) put together a solid bike resource on the web...He has some hints on wheel adjustment (after describing building)<a href="https:&#x2F;&#x2F;www.sheldonbrown.com&#x2F;wheelbuild.html" rel="nofollow">https:&#x2F;&#x2F;www.sheldonbrown.com&#x2F;wheelbuild.html</a>sometimes local bike shops have wheel building classes.

You say you have difficulty adjusting spoke tension but you don&#x27;t say what the problem is. Do you have a spoke tensiometer? I consider it manadatory (you don&#x27;t have to have a fancy electronic one although they&#x27;re a pleasure to use).

&gt; One thing I&#x27;ve noticed is that when you take a sharp turn on a mountain bike, you tend to move the bike away from your body. But on a road bike, you maintain that alignment with your body and the frame.I don&#x27;t know the answer but will toss out a guess.I&#x27;d speculate one of the biggest differences is how each bike is used and its intended design based on that use case. Centrifugal forces combined with traction of tire to surface will be very different between road bike tires at high speed on pavement versus mountain bike tire and low&#x2F;moderate speeds on dirt. Beyond that, a mountain bike is often rode through technical terrain that requires dynamic balance by the rider (rider strategically shifts weight over bike) - whereas road bikes appear to be rode with a more &quot;static&quot; balance between rider and bike.

1. Go around the wheel and use a tension gauge to make all the spokes equivalent in tension. Then go around and fix the lateral and radial runout.2. Has to do with geometry and thickness of the tires.To generalize the article even more, the way a bike turns is like this: for a given speed and radius through a corner, there is a necessary lean angle. That lean angle determines the camber thrust of the tires, which is the centripetal force that makes the bike turn. However, you also have to make the bike yaw, which means the front has to generate a greater sideways force than the rear. This is accomplished through adding steering angle to the front tire. The longer the bike is, the greater the difference that is needed between front and rear sideways forces.Furthermore, the steering angle of the front tire is affected by the head angle (90-rake angle), and geometric trail (caster effect). The greater the geometric trail is, the more the tire wants to resist turning. The greater the speed, the higher this effect. Conversely, the slacker the head angle is (lower in value, greater rake angle), the more the front tire wants to turn into the turn (because the wheel axle lower in height with increasing steering angle).The reason why you generally lean the mountain bikes under you are 2 fold. First, the bikes are longer, so naturally you need the greater difference, which means you need more force from the front. You would exceed the max slip angle of the front tire if you stayed upright, especially on looser dirt. So instead, you lean the bike more to engage camber thrust. Secondly, the tires on mountainbikes are designed with side knobs specifically for cornering, so you want to engage those knobs.The opposite problem exists on street motorcycles, where the bikes need to be low enough to the ground to not backflip on acceleration, which limits the available bike lean angle. So instead, riders learn to hang off the bike. This in turn requires the front end to be turned more. As a consequence of this, bikes understeer or oversteer behavior is greatly depends on the front end geometry (rake and trail). The trail forces are magnified at the higher speeds, so you need careful tuning of things like fork offsets (which control trail), and rake angle, both of which are affected by suspension moving up and down.Yet, on supermoto bikes (i.e dirtbikes with street tires, popular in europe), you don&#x27;t have the ground clearance problem, so you can actually corner them either like street bikes with knee down, or dirt bike style while leaning the bike under you.

&gt; But on a road bike, you maintain that alignment with your body and the frameI used to do this until recently. It is now a bad habit of mine. On a mountain descent you&#x27;ll want to steer that road bike how you would a mountain bike by leaning the bike and counter leaning your body. The more gradual the turn and lower thd speed, the less it will matter.

Hey there fellow bikers!I&#x27;ve been having some trouble adjusting the tension in my spokes lately. It seems like no matter how much I try, I just can&#x27;t seem to get it right. Does anyone have any tips or tricks they could share with me?On a related note, I&#x27;ve been wondering about the differences between mountain bikes and road bikes. One thing I&#x27;ve noticed is that when you take a sharp turn on a mountain bike, you tend to move the bike away from your body. But on a road bike, you maintain that alignment with your body and the frame. It&#x27;s fascinating how these small differences can have such a big impact on the way we ride.What do you all think? Have you noticed any other differences between these two types of bikes? Let&#x27;s chat and share our experiences!

Seems like a right term. I mean, if anything, the length of the article rings the bell.

If you meant nerd sniping, then yes, absolutely!

It might not be intentional, but does anyone think that this article might be a well executed act of trolling?

Wonderful work! While I was reading, the HN points went up 500% and my battery fell by 50%.

I saw the link to this article on Twitter and came here to double-check that it is indeed in the top 5

What a great example! As a recent astronomy enthusiast, I found myself doubting this comment initially (&quot;well, eclipses ARE related&quot;), and this despite the fact that I have a toy tellurion right by my desk.But hearing a particular phrase in the below video helped correct my model. One sanity check is that you can see non-full moons during the day (although I definitely would have just assumed it was still a matter of angles).Related video: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Jip3BbZBpsM">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Jip3BbZBpsM</a>

&gt; remind myself that knowing the name of something is not knowing about somethingYou and Feynman both: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;px_4TxC2mXU" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;px_4TxC2mXU</a>

I was just talking to a friend about moon phases the other day, saying that I&#x27;d never really understood why it does what it does, only that vaguely things rotate around each other and this waves hands does things.He explained it like this which really helped: you can choose all sorts of frames of reference when you think about this stuff, so choose one where the sun and earth are stationary compared to each other, and then only the moon is rotating - less stuff to think about!Now you&#x27;ve got the earth spinning very fast in the middle, the sun sitting off to one side, and the moon then goes in a slow circle around the earth. If it&#x27;s on the opposite side of the earth to the sun, then it&#x27;s going to be fully lit up, but it&#x27;s also only going to be visible at night. If it&#x27;s on the same side as the sun, then the side that&#x27;s facing us is going to be dark and difficult to see, but it will be in the sky during the day, which is why occasionally the moon is visible in daytime, even though we all know the moon comes out at night.I think that idea of changing your perspective - in this case, literally, by changing the frame of reference - is really helpful when it comes to understanding things that we only know about. Like, I&#x27;ve known about the solar system since I was a kid, I&#x27;ve seen all of the models, I surely made my own as a schoolchild - the knowledge is all there! But for understanding, I needed to find a new perspective.That&#x27;s probably true of the bike thing as well, thinking about it. Knowledge of a bike is easy: it&#x27;s two wheels, handlebars, a seat, and pedals. But understanding how a bike is made requires thinking about the frame, and that&#x27;s just a squashed parallelogram with a stick coming out of it. Once you visualise that, it becomes really obvious how the rest of the bike gets put together, but the frame is necessary for understanding. Otherwise, you just put together the things you know about and then have to draw awkward lines in between to connect them.

I 100% agree with your comment however in regards to it&#x27;s relationship to the parent comment I have to disagree somewhat in the usual nitpicky hackernews fashion:Asking someone to draw &quot;a bicycle&quot; is different to asking them to draw a specific bicycle or a functional bicycle. Also what does it mean to &quot;know something&quot;?If you ask someone to draw a house and they draw a square with an overhanging equilateral triangle centred on top, it&#x27;s not that they don&#x27;t know what a house is. That&#x27;s just a symbol representation of their own personal definition of a house.

&gt; The classic example is asking people to describe the process that causes the phases of the moon. Most (myself included the first time) describe an eclipse, which is wrong.To me, a neat consequence of this is that if you know what part of the cycle the moon is in, you know where it will be relative to the sun in the sky (and vice versa).

&gt; how our brain sometimes tricks us into thinking we know something even though we don’tThe way I try to avoid this is to remind myself that knowing the name of something is not knowing about something, only about the existence of that something.There are lots of things I know the names of, but relatively few things I actually know about.The classic example is asking people to describe the process that causes the phases of the moon. Most (myself included the first time) describe an eclipse, which is wrong.

Reminds me of how AI image generators draw stuff slightly wrong

Came here to post this. I would love to see all the same force animations but with these models swapped into them.

Sounds like you’ve spent a lot of time experimenting! Got any pics of the weird bicycles?

Nothing about the rendering specifies that the frame isn&#x27;t made of solid steel rods.Aren&#x27;t you assuming that it&#x27;s a tube of the same thickness as a typical bike?And furthermore, that someone building it wouldn&#x27;t be allowed to make obvious accomodations to reinforce the parts of the frame under stress?E.g. [1] shows a bike for sale with similarly lacking bracing of the head tube.1. <a href="https:&#x2F;&#x2F;cowboy.com&#x2F;products&#x2F;e-bike-cowboy-4?variant=41191037370507" rel="nofollow">https:&#x2F;&#x2F;cowboy.com&#x2F;products&#x2F;e-bike-cowboy-4?variant=41191037...</a>

The trouble with the very first render is that the author is wrong about why the bike wouldn&#x27;t work. The head tube isn&#x27;t braced well enough to allow the front brake to be used, and would twist when cornering to a degree that would unsettle most riders. The missing chainstay would only be an issue for powerful cyclists or people standing up to pedal. But the bicycle shown could definitely be built and ridden. Probably more practical than Saul Griffith&#x27;s plexiglass bicycle (that was also built and ridden).At one stage Klein had a problem with the chainstays separating at the bottom bracket and a number of people rode those bikes after breaking them... almost exactly the &quot;missing chainstay&quot; problem above.I&#x27;ve built some very weird bicycles and broken both those and conventional bicycles. I have at least some idea of what works... I&#x27;d be willing to build as many of those renders as someone was willing to pay for.

this was one of the greatest installations i&#x27;ve ever seen in an art gallery.  You have no idea what you&#x27;re looking at until you&#x27;ve passed through all the rooms...seeing a real life &quot;fucked up&quot; bike in the last room...is a little mind blowing haha

Relevant link that I saw on HN earlier this week: someone asks people to sketch bicycles and then renders the sketches.<a href="https:&#x2F;&#x2F;www.gianlucagimini.it&#x2F;portfolio-item&#x2F;velocipedia&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.gianlucagimini.it&#x2F;portfolio-item&#x2F;velocipedia&#x2F;</a>&gt; Little I knew this is actually a test that psychologists use to demonstrate how our brain sometimes tricks us into thinking we know something even though we don’t.&gt; I collected hundreds of drawings, building up a collection that I think is very precious. There is an incredible diversity of new typologies emerging from these crowd-sourced and technically error-driven drawings. A single designer could not invent so many new bike designs in 100 lifetimes and this is why I look at this collection in such awe.

Surprised that the reason the frame is hollow is for structural reason rather than to just save weight.

This guy&#x27;s content is seriously top notch. His recent article on Sound from a few months ago was astounding and probably the best article I&#x27;ve seen posted here.

All those mechanics are explained further down. There is a whole segment in the visualizations dedicated to steering and how you steer the othet way first.

the animation is wrong. It shows the wheel of the bike turning into the turn as the rider leans over.In reality, the wheel turns slightly away from the turn. This is called &quot;counter steering&quot;<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Countersteering</a>

Super intuitive learning physics this way

That’s gotta be a cool feeling to see your work cited in other research. Kudos!

Never thought about, but yeah I guess it makes sense. If you were to suddenly stop you would be jolted forward, so need to get a bit behind the wheel first.(too late to edit my original comment, but here is a link to my thesis discussed at the time: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10410813" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10410813</a> )

Unicycles have a similar counter-intuitive control method where you need to accelerate the wheel to slow down and vice versa. Turning doesn&#x27;t work quite the same way though as you can do sharp turns by twisting your hips and thus changing the direction that the wheel is pointing.

Never heard of it. Show us this... the wheel

I also recommend the SmarterEveryDay video[0] where they rig a bike to turn the opposite way than it is steered.[0] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=MFzDaBzBlL0">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=MFzDaBzBlL0</a>

When I took control theory at university, in the last lecture, the lecturer took out a bike with rear wheel steering and challenged us to ride it in the hallway outside the lecture hall in the break. No one could get it to roll more than a couple of meters. The second half of the lecture was spent proving that a rear wheel steered bike is in fact (almost) impossible to control.

&gt; opposite direction turningThe term used in motorcycling is countersteering. A lot of people think they are using their body to change direction but that would not be sufficient. Also it helps to be deliberate about the handlebar pushing motion for safety and performance.

Veritasium did a great video on the opposite direction turning. They even show a bike that prevents you from turning the wheel one way to show that its essential.<a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=9cNmUNHSBac</a>

No, it&#x27;s because there&#x27;s not enough room to counter-turn to shift your balance.

You often see these two concepts (target fixation and counter-steer) discussed in threads on steering.Not denying that target fixation is real and operative in some circumstances ... but counter-steer is even more &quot;basic&quot; in that it is solely a function of two-wheel dynamics, not rider psychology. You really do need to steer slightly right in order to initiate a turn to go left.See the video linked up-thread.Here&#x27;s a page from a motorcycle POV which has a &quot;truck pulls alongside&quot; anecdote similar to your &quot;riding parallel to curb&quot; example: <a href="https:&#x2F;&#x2F;www.insurance.harley-davidson.com&#x2F;the-open-road&#x2F;tips&#x2F;countersteering-on-a-motorcycle-correctly" rel="nofollow">https:&#x2F;&#x2F;www.insurance.harley-davidson.com&#x2F;the-open-road&#x2F;tips...</a>

The “kerb sucks you in” phenomenon is target fixation, you’re getting closer to the kerb because you’re staring at it. It’s a common cause of motorbike accidents, among other things.<a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Target_fixation" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Target_fixation</a>

This is an important concept when riding motorcycles at higher speeds.  This was taught in the class I took to get my motorcycle license.

Similar to the &#x27;bees can&#x27;t fly&#x27; thing. I never, ever crashed my bike until i learned how not to. And where not to look.

Similar concept that gets a lot of people in trouble on the OneWheel, &quot;lean forward to slow down&quot;. When you&#x27;re going to fast, the you intuitively lean back, which actually accelerates. There&#x27;s even been a handful of lawsuits around this physics issue.

It is unconscious and you have no idea you&#x27;re doing it.Watch the Veritasium video linked earlier. It&#x27;s good stuff.

Interestingly, I read about this a long time ago and intentionally turn the handlebars the wrong way to initiate the lean.  (Not because it&#x27;s necessary, but because it&#x27;s weird.  Riding your bike can be boring at times.)  Very smooth.

Countersteering helps initiate that lean more quickly than just organic falling over.  It&#x27;s possible you&#x27;re exceptionally patient but it&#x27;s also possible you&#x27;re just countersteering a little bit to initiative the lean, without noticing it.

Yeah on a motorcycle leaning doesn’t do anything to engage a turn. “Push the direction you want to go” is what’s drilled into you and also just feels natural.

How thick are your tires? Initiating the turn requires just the tiniest bit of countersteer on very thin tires, in my unstudied experience. I did the same experiment as you and found it was so subtle as to be basically unnoticeable.

The welding the bars experiment you are talking about is done in a motorcycle school I once took with Kieth Code (California Superbike School), in order to prove to riders that countersteering is real.I held an American Pro Superbike racing license in my 20s and countersteering is the only way I ever steered. Here is an experiment - go into a flat and wide open space like a parking lot, ride straight, and then turn to the right hard while keeping straight up and down. Hold the pressure to the right and I promise you will turn left or will initiate a turn to the left. The harder you turn the bars right the quicker the bike will fall left and begin arcing left.In chicanes on a circuit track you can flip the bike over from one side to the other extremely quickly doing this. I&#x27;ve done this on everything from mountain bike to superbike, the latter being a more pronounced effect.The only time I don&#x27;t countersteer is when doing a 180-ish degree turn on a dirtbike, like what is common on an SX course. Also, when doing an extremely slow turn on a sport motorcycle, like what&#x27;s common in USA motorcycle safety courses. But when moving at speed I always countersteer.Knowing this phenomenon and using it may save your life.

It&#x27;s easy to see countersteering in action if you have a quiet damp road. Try riding in a straight line and then turning to the right. Then dismount, walk back to where you started your turn, and have a look at your tyre tracks.

There&#x27;s a YouTube video where they do exactly this.  It doesn&#x27;t end well for the rider.

Many times I&#x27;ve observed myself as closely as I can taking a turn. I can&#x27;t observe any steering in the opposite direction. I start by leaning, then turn into it (if I turn the wheel at all, which I don&#x27;t unless the turn is very sharp). Maybe I really do steer the other way some imperceptible yet vital amount? This summer I plan to weld a bicycle unsteerable and see what happens when I try to steer solely by leaning as it feels like I generally do.

With motorcycles, you gotta learn “push right to go left” or you’re gonna end up in a bad sitch! But the physics of it are pretty mind boggling.

Yes. On a motorcycle at high speed you have to actively maintain force on the wheel towards the outside of the turn to keep in the turn. If you stop the bike will straighten up.

Indeed, if you want to make fast turns at speed on a motorbike the trick is to first push&#x2F;pull the bars in the oppositive direction - that gets the bike leaning over and then the bars come back and take the natural position for the turn. It&#x27;s amazing how quickly even a big, heavy bike (e.g. BMW tourer) willl lean over with the right technique. At very highspeeds it takes quite a bit of muscle too.

The counterintuitive turn is more pronounced in motorcycles. You are literally pushing against the turn as you lean into the turn, and to lean in you have to turn out. Even more pronounced in sport motorcycles. Maintaining the centre of gravity during a lean at those speeds is a lot of fun to master. It’s one of those heart racing moments, literally no room for error.

It was mainly a CS thesis on multi-objective optimization algorithms, and wheels were my chosen application. So me not being a mechanical engineer I didn&#x27;t exactly push that side of the science any forward.But my algorithm did end up &quot;inventing&quot; the 3x pattern perfectly, which I think was cool. Both as a confirmation that it&#x27;s really a good versatile pattern being pareto optimal in multiple objectives, and the algorithm finding it also verified that my approach did have some merit.Of the &quot;unconventional&quot; ones it found, my favorite I ended up using for the cover: <a href="https:&#x2F;&#x2F;i.imgur.com&#x2F;b1ImCo8.jpg" rel="nofollow">https:&#x2F;&#x2F;i.imgur.com&#x2F;b1ImCo8.jpg</a>

Get a copy of the Bicycle Wheel by Jobst Brandt.(and then try to map that experience onto current spokes&#x2F;rims, which are somewhat different)

&gt; I wrote my master thesis on optimizing bicycle wheels &#x2F; spokes.Any practical outcomes for hobby wheelbuilders with conventional parts (like some sort of novel lacing pattern or something like that)?

Drop the space between &quot;bak&quot; and &quot;fiets&quot;. Just &quot;bakfiets&quot;, otherwise you don&#x27;t mean the noun for cargo bike, but the imperative &quot;bake a bike&quot; ;)

Target fixation - you&#x27;ll go where you look, for better or worse.  Inexperienced riders will often stare right at the obstacle they&#x27;re trying to avoid and ride right into it.

You went bakfiets shopping as a novice rider?Sounds brave. Did it work out?

&gt; ..you sometimes can feel the curb &quot;sucking&quot; you towards it when you try to avoid itI was shopping for a kids carrying bikes, called bakfiets[1] (I think) in the Netherlands. The salesperson offered me a trial ride, his advice is something I still remember. Don&#x27;t bother about the front wheels (they are far out in front), just look where you want to go and your hands will take care of steering and balancing.[1] <a href="https:&#x2F;&#x2F;www.bakfiets.com" rel="nofollow">https:&#x2F;&#x2F;www.bakfiets.com</a>Edit: fixed thanks to the correction by “isoprophlex”!

Gyroscopic forces are fun. That phenomenon kicks in around 20-25 mph but that’s when I was on a crotch rocket. I’ve experienced it at like 15 mph on a bicycle.

But why can&#x27;t the inability to make a sharp turn be explained by the need to arrest forward momentum? The momentum has to change direction. Turning 90 degrees causes sudden loss in velocity. Turning against the arc of the turn i.e. along the orbit of the turn transfers the forward momentum into angular momentum. Thus, a counterturn is just an efficient way for the bike to follow the arc.Higher the velocity, the larger the arc required.

I can at least confirm that my daughter was very much surprised when her balance bike [0], which is essentially a small draisine, stayed upright when she lifted her legs.[0] <a href="https:&#x2F;&#x2F;cdn.thewirecutter.com&#x2F;wp-content&#x2F;uploads&#x2F;2017&#x2F;12&#x2F;balance-bike-lowres-1540.jpg" rel="nofollow">https:&#x2F;&#x2F;cdn.thewirecutter.com&#x2F;wp-content&#x2F;uploads&#x2F;2017&#x2F;12&#x2F;bal...</a>

I read once that when draisiennes first appeared in 1817, it was a surprise to the inventor that you could in fact lift your legs up and balance.I forget completely where I might have read or heard this, but I love it so much I&#x27;m going to keep telling it. Can anyone confirm?

I wrote my master thesis on optimizing bicycle wheels &#x2F; spokes. I actually see I&#x27;m cited in the phd he cites, quite a fun surprise!This is a great article. It showcases lots of the &quot;simple, but surprisingly advanced&quot; things surrounding bicycles. Which was what got me hooked in the first place. The visualization of how you have to turn right to go left is excellent. I&#x27;ve mentioned that fact multiple times here on HN, it&#x27;s not commonly known, you just &quot;do it&quot; when you bike! And it explains why you sometimes can feel the curb &quot;sucking&quot; you towards it when you try to avoid it: you unconsciously avoid turning the wheel towards it, but that actually makes it so that you&#x27;re unable to actually steer away from it!

Some (good) e-cars burn ~250Wh per mile.Humans burn something like 750Kc per hour on a bike, and go 15 milesA Wh is ~1Kc (0.8:1 but ok)That makes bikes, what, 5X more efficient?

This is another awesome post, although it doesn&#x27;t address the one thing about bicycles I can never remember - which of the pedals has a reverse-threaded attachment to the pedal crank arm, and what&#x27;s the complete force-based explanation for this necessity?I&#x27;m not even sure if the force responsible for this is friction-related, or torque related, or some combination of both (probably the latter). The force is transmitted to the chaindrive in an off-axis manner, but the pedal itself is further removed from the axis, so when you push down on the pedal axis that&#x27;s ahead of the bottom bracket axis - one side will tighten clockwise from the pedal&#x27;s perspective, and the other side will tighten anti-clockwise.Wow I got it right after going through this post! That&#x27;s a first, though I&#x27;m still not sure I got all the forces right.