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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How the shadow cabinet forced Jeremy Corbyn not to change Labour policy on Syria air strikes

Frontbenchers made it clear that they "would not leave the room" until the leader backed down. 

Jeremy Corbyn had been forced to back down once before the start of today's shadow cabinet meeting on Syria, offering Labour MPs a free vote on air strikes against Isis. By the end of the two-hour gathering, he had backed down twice.

At the start of the meeting, Corbyn's office briefed the Guardian that while a free would be held, party policy would be changed to oppose military action - an attempt to claim partial victory. But shadow cabinet members, led by Andy Burnham, argued that this was "unacceptable" and an attempt to divide MPs from members. Burnham, who is not persuaded by the case for air strikes, warned that colleagues who voted against the party's proposed position would become targets for abuse, undermining the principle of a free vote.

Jon Ashworth, the shadow minister without portfolio and NEC member, said that Labour's policy remained the motion passed by this year's conference, which was open to competing interpretations (though most believe the tests it set for military action have been met). Party policy could not be changed without going through a similarly formal process, he argued. In advance of the meeting, Labour released a poll of members (based on an "initial sample" of 1,900) showing that 75 per cent opposed intervention. 

When Corbyn's team suggested that the issue be resolved after the meeting, those present made it clear that they "would not leave the room" until the Labour leader had backed down. By the end, only Corbyn allies Diane Abbott and Jon Trickett argued that party policy should be changed to oppose military action. John McDonnell, who has long argued for a free vote, took a more "conciliatory" approach, I'm told. It was when Hilary Benn said that he would be prepared to speak from the backbenches in the Syria debate, in order to avoid opposing party policy, that Corbyn realised he would have to give way. The Labour leader and the shadow foreign secretary will now advocate opposing positions from the frontbench when MPs meet, with Corbyn opening and Benn closing. 

The meeting had begun with members, including some who reject military action, complaining about the "discorteous" and "deplorable" manner in which the issue had been handled. As I reported last week, there was outrage when Corbyn wrote to MPs opposing air strikes without first informing the shadow cabinet (I'm told that my account of that meeting was also raised). There was anger today when, at 2:07pm, seven minutes after the meeting began, some members received an update on their phones from the Guardian revealing that a free vote would be held but that party policy would be changed to oppose military action. This "farcical moment", in the words of one present (Corbyn is said to have been unaware of the briefing), only hardened shadow cabinet members' resolve to force their leader to back down - and he did. 

In a statement released following the meeting, a Corbyn spokesperson confirmed that a free vote would be held but made no reference to party policy: 

"Today's Shadow Cabinet agreed to back Jeremy Corbyn's recommendation of a free vote on the Government's proposal to authorise UK bombing in Syria.   

"The Shadow Cabinet decided to support the call for David Cameron to step back from the rush to war and hold a full two day debate in the House of Commons on such a crucial national decision.  

"Shadow Cabinet members agreed to call David Cameron to account on the unanswered questions raised by his case for bombing: including how it would accelerate a negotiated settlement of the Syrian civil war; what ground troops would take territory evacuated by ISIS; military co-ordination and strategy; the refugee crisis and the imperative to cut-off of supplies to ISIS."

George Eaton is political editor of the New Statesman.