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« Maintaining my racing weight | Main | Curious goings on »
Monday
Jul252016

When science finds problems that don’t exist

Several people emailed me with a link to this article in Scientific American.

I am familiar with some of the people and the work outlined in the article, because five years ago I wrote a piece about it.

Jim Papodopoulis, (Left.) featured in much of the Scientific American article, wrote an extremely lengthy 2,200 word response in the comments section and invited me to reply.

At the time I stated that I was not prepared to write a similar length reply, but would discuss the subject over the phone. There never was a follow up phone call.

There is an old British saying that goes, ‘Bull shit baffles brains.’ And clever sounding waffle can impress, especially if published in a notable magazine. But analyze the piece and it says nothing of value. The SA article states:

Everybody knows how to ride a bike, but nobody knows how we ride bikes. 

Of course there are people who know how we ride bikes, but most just do and don’t try to over think it. One of the purposes of this blog is to explain the workings of a bicycle in a simple manner.

So how do we balance on a bike? The gyroscopic action of the spinning wheels is only one little piece of the equation. Actually, when riding slowly, (As slow as you possibly can.) The slowly turning wheels generate hardly any gyroscopic force, and so have little or no effect on staying upright.

It is a simple balancing act, like balancing an upturned broom on your hand. You constantly move your hand to keep it under the center of mass. (The broom head.)

In fact it is easier to balance a broom than it is to balance a broom handle without the head. Therein lies a clue. It is because the center of mass is high above the palm of your hand. Just as when riding a bike the center of mass, (The rider’s body.) is some four feet above the point of contact. (The tires on the road.)

It is almost impossible to ride a bike slowly in a straight line. It is a constant steering the bike left and right to keep the wheels directly under the center of mass. You can even ride slowly ‘no hands.’ It then takes movement of the hips and upper body to remain balanced. Much the same way as riding a skate board, which has very little gyroscopic help from its tiny wheels, or a surf board that has no wheels.

Then as you gather speed it is the momentum of the body’s mass that keeps you upright and going straight. The faster you go the easier it is to balance and to steer left and right by simply leaning left and right. A surfer too, when going slow is constantly moving his body to stay upright. As soon as he catches a big wave and is traveling at speed, he easily stays upright and steers left and right by leaning in that direction.

So how we balance on a bike is no huge mystery, it is a kin to surfing, skating, and many other human activities that become second nature with a little practice. And yes, things like frame geometry and gyroscopic action enter into it. Here is a link to a previous article I wrote on head angles and steering, that explains further. It also explains counter steer, which according to the Scientific American article is another mystery that no one knows about.

I did a quick YouTube search to see if there was any progress on the work on the “Riderless Bike.” I found this little video from last year.

The bicycle, one of the simplest and most efficient machines ever invented by man. Two wheels make it efficient, more efficient than three or four wheels that most other vehicles need to stay upright.

For all useful purposes it requires a rider in order to stay upright. And although it will stay upright for a brief moment without one, if it does not have a rider, what is the point of a bicycle or motorcycle? It is not a practical vehicle to carry anything other than a human passenger.

The bicycle is a mechanical extension of the human body. Riding one is a simple skill that even a small child can master. Once learned it becomes intuitive, a skill that lasts a lifetime, no more difficult than walking or running.

The bicycle has changed little over the 130 odd years since the chain driven bike appeared. There is a reason for that. It has to do with the old saying that goes. “If it ain’t broke, don’t fix it.” Even if the math doesn’t add up.

I believe science, in this case, is trying to find answers to problems that don’t exist. The fact that the world wide bike industry is not exactly lining up to buy into the new tech is another clue that nobody cares.

 

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Reader Comments (19)

That's further away from the road than a self-driving car. You might be able to describe how we ride a bicycle but trying to get a computer to do it requires a model that works, which is a different sort of description. Problems that don't exist? This is curiosity-driven science, it looks great fun. Nothing of value? Of value to whom? You are looking for the application, they are just looking for answers to problems that can be described and therefore exist, of only intellectually.

July 25, 2016 | Unregistered Commenterpeter

"The bicycle, one of the simplest and most efficient machines ever invented by man.."

Efficiency is a matter of definition. A bike might be efficient in terms of energy input vs distance covered, but it's not very efficient in terms of getting a family of four from Yorkshire to Cornwall for a fortnight's camping and surfing holiday.

July 25, 2016 | Unregistered CommenterMick Sperry

Mick,
A tandem for you and the misses, a trailer for the kids and all your gear. From Yorkshire to Cornwall is down hill all the way, and on the way back you will have the wind behind you :)
Dave

July 25, 2016 | Registered CommenterDave Moulton

The behaviour of the experimenters reminded me of parents running behind a child learning to ride a bike, I'm sure the emotions are pretty similar after all, it's their brainchild on that bike.

July 25, 2016 | Unregistered Commenterpeter

Here is part of the jest of “Nobody knows how we do it.”:

No computer in the world can, nor will ever, draw a perfect circle. A perfect circle can only exist in nature. Why? It’s about resolution and the language of computers. Any circle done with a robot, or computer, is really steps, linear, and not circular (called circular interpolation).

So also the difference between digital photos and film. Film is organic, digital is numbers assigned to colors, and as you increase the resolution, you see space between those representations.
Therefore, there is a lot of missing information, or open space, in all things related to computers. Our minds fill in the blanks, and convince ourselves it represents reality.

Funny how the telegraph is digital, and when phones came out, we all became endeared to analog, and now, everything has gone back to digital.
Guess we all have to fill in the blanks…to make it real.

July 25, 2016 | Unregistered CommenterSteve

Dave, I saw that article too but didn't bother to read it. But as a former frame builder, I'd like to ask you a question. It would even make a good subject for a blog if you know the answers.

What makes a bike easy to ride no-hands? I've never been very good at it, but have noticed some bikes are easier than others. I was particularly impressed to see the Sky Team riding all abreast with their hands on each others shoulders at the end of the Tour de France. Are these bikes especially designed to ride no hands because of how often the riders need to do that?

July 26, 2016 | Unregistered CommenterJohn B

John B,
Riding no hands, I believe has more to do with the confidence and skill of the rider. These are pros, it is what they do all day and every day for a living. I have also yet to see a pro get in a speed wobble. (Shimmy.) And yet the forums are full of accounts of riders experiencing shimmy at speeds around 40-45mph. Riding Treks, Specialized, etc the very same bikes. I believe it has more to do with the rider.
Dave.

July 26, 2016 | Registered CommenterDave Moulton

.......a skill that lasts a lifetime, thank goodness, like swimming.

July 27, 2016 | Unregistered CommenterAnthony C.

....no hands ? I've had bikes on which that was easier than others. Maybe due to the brake and gear cable set up ? But I've never given it much thought.

July 27, 2016 | Unregistered CommenterAnthony C.

I had a 1953 Hetchins with the curly stays. It was impossible to ride, no hands due to shimmy, had to press my knee against the cross bar to control it. Had no problem with any other bike I have ever owned. It was also not a good climbing bike.

July 27, 2016 | Unregistered Commenterjohn crump

Talk about no hand riding. In the TDF one rider, was riding no hands zipping up his jersey, going UPHILL now that takes skill

July 27, 2016 | Unregistered Commenterjohn crump

I loved my old ALAN aluminium frame but what a wobbler it was !

July 27, 2016 | Unregistered CommenterAnthony C.

John B,

How easily a particular bike rides "no hands" largely comes down to how well the fork and the frame are aligned to each other. If everything is in perfect alignment, the natural position the fork wants to rest in, due to "trail" puts the rider's center of gravity directly in line with the tires. If the fork or frame is off, the rider's CG will be off to one side or the other. To compensate, you would have to lean some just to keep it straight. That lean effects the rest position of the front wheel, requiring further input. Worse, the fork will respond differently to the left or right, making corrections very non-linear. (not impossible to ride, just harder, to maybe much harder depending on the degree of mis-alignment.)

As proof, I've had one or two frames that were quite hard to ride "no hands" always pulling to one side, and very hard to keep straight. Careful checking of forks and frames found that one had a fork that was offset to the left by about 5/16", and the other had about 1/8" of fork offset, as well as a rear triangle that was probably cold set from 120mm to 126mm, but all the bending was done on one side, pulling the alignment off. After several rounds of "careful" brute force and re-checking things, they're now both straight. They're quite easy to ride "no hands", showing no tendency to pull to either side, and are quite controllable.

July 31, 2016 | Unregistered CommenterCameron Murphy

You make some good points, Cameron. I've developed scoliosis over many rears and someone riding behind me has noticed I don't sit straight on the saddle. No doubt that doesn't help riding no hands.

July 31, 2016 | Unregistered CommenterJohn B

I suspect that when you say it's a problem that doesn't exist, you're asking an engineering question - how do we make a bicycle that is ridable?

Mr. Papodopoulis and his colleagues are asking a science question: why is a bike ridable? They aren't trying to solve a problem. They are trying to understand a phenomenon.

And the thing about science is you don't know where it will lead. Understanding an unstable system like a bicycle may lead to better controls for other unstable systems, like rockets.

August 2, 2016 | Unregistered CommenterZed Fecten

Phil Wood: "A bicycle stays up because it wants to. It has nothing to do with science."

August 3, 2016 | Unregistered CommenterTimJ

Riding a bicycle has nothing to do with science.

Just as we will never know how Mozart wrote music, or Isaac Newton thought up new concepts, or Michelangelo sculpted beautiful forms, so to, the author of said studies. No wonder frame builders avoided him.

For one small example to behold: Saddle Height. It isn’t based on any scientific facts. It is only a culmination of collected data, which in itself may be scientific, or more accurately, mathematical, since the result is an average, or percentage of the data collected. And there are as many variables as there are subjects.

Thus the enigma: How do we do it? The only reason to ask is so it can be take away…I avoid those people also!

August 4, 2016 | Unregistered CommenterSteve

Good Article. What was American Scientific thinking?

Both Cornell and MIT have easy-to-understand explanations of how bikes stay upright, and they've done practical experiments to prove the math.

Both of them seem to refute some of the findings in the AS article.

https://www.news.cornell.edu/stories/2011/04/researchers-explain-why-bicycles-balance-themselves

https://ocw.mit.edu/courses/experimental-study-group/es-010-chemistry-of-sports-spring-2013/lecture-notes/MITES_010S13_lec6.pdf

September 25, 2016 | Unregistered CommenterScott

Dear Dave,

if you need any further support for your argument: occasionally I talk friends into riding dirt and trails with their roadbikes (those friends that aren't already into it). When they hesitate I actually tell them that it's just like surfing - that their weight is many times more than that of the bike, and that if the bikes is skidding or fishtailing they just should keep cool and let the momentum of their body work for them, move the bike under them, catch it back. Thus, at the same time I can convince them that it might be better to go faster, instead of too slow. It worked wonders even with some anxious characters.

Well, didn't say that to brag (also not to say that there aren't limits to road bikes on dirt etc.). Just that it baffles me how simple it actually is, and that this simple fact gets so little attention. Took me some time to understand it, too. Got it intentionally right early, because I didn't worry - but took some years to be able to explain it. Nobody told me before! So just like kids riding for the first time, adults need to put trust in the rider-bike system again and again.

Thanks for the article from an occasional reader. First time I found this argument on the web.

October 25, 2016 | Unregistered CommenterOscar Dube

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