We still don’t really know how bicycles work

Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.

Let’s be honest, a bit of the pleasure at Chris Froome’s victory in the Tour de France is down to this being our second victory in a row and to the thought that the French haven’t won it since 1985. What must be worse for them, though, is that when it comes to the science of team cycling, even the Belgians are in front.
At the University of Mons, researchers are developing something called the Anaconda. It’s never going to be much of a speed machine because it is, in effect, a chain of monocycles with handlebars. These units are connected, by means of hinges that allow them to snake along, to a normal two-wheeled bike at the front. Every rider in the chain can be going in a slightly different direction, which means it takes an enormous amount of control and collaboration to move the thing forward. According to Olivier Verlinden, chief engineer on the project, the main qualification for riders is to be unafraid of falling off.
It’s fun, apparently. The idea is to unleash it as a beach-resort bike, the kind of thing that stag and hen parties will use to terrorise seaside towns across the world. But it is also scientifically interesting. Why? Because we still don’t really know how bicycles work.
It is rare that most people appreciate the bicycle, but it is quite an extraordinary machine. Push a riderless bike, letting it roll freely at high enough speeds, and it can withstand pushes from the side – it will wobble a little, but quickly recover. In the conventional analysis, that is because the gyroscopic force of the front wheel, its mass and the spontaneous turn of the handlebars all act together to keep the bicycle rolling forwards. This has something to do with the gyroscopic effect, the force that keeps a spinning top upright. You can feel this by removing a wheel from your pushbike and spinning it while you hold the axle spindles. If you try to change the orientation of the wheel, you’ll feel it push back against you.
The first mathematical analysis of bicycles suggested that this is also what keeps a moving bike on its wheels. But although the equations were written down in 1910, physicists always had nagging doubts about whether this was the whole story.
The most definitive analysis came exactly a century later. It involved an experimental bicycle that had all its gyroscopic effects cancelled out by a system of counter-rotating wheels. The effort of building such a strange contraption was worth it: the resulting paper was published the prestigious journal Science.
The publication plunged bicycle dynamics back into chaos. It turns out that taking into account the angles of the headset and the forks, the distribution of weight and the handlebar turn, the gyroscopic effects are not enough to keep a bike upright after all. What does? We simply don’t know. Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.
And it may not be solved any time soon; very few researchers are working full-time on bicycle dynamics and there’s very little money in it. Once we’ve discovered exactly how these contraptions work, it might be possible to come up with bold new designs of bicycle – perhaps even better than the Anaconda. But nobody is desperate for that to happen; not even the French.
Maybe that’s OK. In an age where we have worked out the history of the cosmos and the secret of life, it’s rather nice that the humble bicycle keeps our feet on the ground. 
Cyclists during the Tour de France. Photo: Getty

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 29 July 2013 issue of the New Statesman, Summer Double Issue

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I'm far from convinced by Cameron's plans for Syria

The Prime Minister has a plan for when the bombs drop. But what about after?

In the House of Commons today, the Prime Minister set out a powerful case for Britain to join air strikes against Isil in Syria.  Isil, he argued, poses a direct threat to Britain and its people, and Britain should not be in the business of “outsourcing our security to our allies”. And while he conceded that further airstrikes alone would not be sufficient to beat Isil, he made the case for an “Isil first” strategy – attacking Isil now, while continuing to do what we can diplomatically to help secure a lasting settlement for Syria in which Assad (eventually) plays no part.

I agreed with much of David Cameron’s analysis. And no-one should doubt either the murderous barbarism of Isil in the region, or the barbarism they foment and inspire in others across the world.  But at the end of his lengthy Q&A session with MPs, I remained unconvinced that UK involvement in airstrikes in Syria was the right option. Because the case for action has to be a case for action that has a chance of succeeding.  And David Cameron’s case contained neither a plan for winning the war, nor a plan for winning the peace.

The Prime Minister, along with military experts and analysts across the world, concedes that air strikes alone will not defeat Isil, and that (as in Iraq) ground forces are essential if we want to rid Syria of Isil. But what is the plan to assemble these ground forces so necessary for a successful mission?  David Cameron’s answer today was more a hope than a plan. He referred to “70,000 Syrian opposition fighters - principally the Free Syrian Army (FSA) – with whom we can co-ordinate attacks on Isil”.

But it is an illusion to think that these fighters can provide the ground forces needed to complement aerial bombardment of Isil.  Many commentators have begun to doubt whether the FSA continues to exist as a coherent operational entity over the past few months. Coralling the myriad rebel groups into a disciplined force capable of fighting and occupying Isil territory is a heroic ambition, not a plan. And previous efforts to mobilize the rebels against Isil have been utter failures. Last month the Americans abandoned a $500m programme to train and turn 5,400 rebel fighters into a disciplined force to fight Isil. They succeeded in training just 60 fighters. And there have been incidents of American-trained fighters giving some of their US-provided equipment to the Nusra Front, an affiliate of Al Qaeda.

Why has it proven so hard to co-opt rebel forces in the fight against Isil? Because most of the various rebel groups are fighting a war against Assad, not against Isil.  Syria’s civil war is gruesome and complex, but it is fundamentally a Civil War between Assad’s forces and a variety of opponents of Assad’s regime. It would be a mistake for Britain to base a case for military action against Isil on the hope that thousands of disparate rebel forces can be persuaded to change their enemy – especially when the evidence so far is that they won’t.

This is a plan for military action that, at present, looks highly unlikely to succeed.  But what of the plan for peace? David Cameron today argued for the separation of the immediate task at hand - to strike against Isil in Syria – from the longer-term ambition of achieving a settlement in Syria and removing Assad.  But for Isil to be beaten, the two cannot be separated. Because it is only by making progress in developing a credible and internationally-backed plan for a post-Assad Syria that we will persuade Syrian Sunnis that fighting Isil will not end up helping Assad win the Civil War.  If we want not only to rely on rebel Sunnis to provide ground troops against Isil, but also provide stable governance in Isil-occupied areas when the bombing stops, progress on a settlement to Syria’s Civil War is more not less urgent.  Without it, the reluctance of Syrian Sunnis to think that our fight is their fight will undermine the chances of military efforts to beat Isil and bring basic order to the regions they control. 

This points us towards doubling down on the progress that has already been made in Vienna: working with the USA, France, Syria’s neighbours and the Gulf states, as well as Russia and Iran. We need not just a combined approach to ending the conflict, but the prospect of a post-war Syria that offers a place for those whose cooperation we seek to defeat Isil. No doubt this will strike some as insufficient in the face of the horrors perpetrated by Isil. But I fear that if we want not just to take action against Isil but to defeat them and prevent their return, it offers a better chance of succeeding than David Cameron’s proposal today. 

Stewart Wood is a former Shadow Cabinet minister and adviser to Ed Miliband. He tweets as @StewartWood.