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

Photo: Getty
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Jeremy Corbyn sat down on train he claimed was full, Virgin says

The train company has pushed back against a viral video starring the Labour leader, in which he sat on the floor.

Seats were available on the train where Jeremy Corbyn was filmed sitting on the floor, Virgin Trains has said.

On 16 August, a freelance film-maker who has been following the Labour leader released a video which showed Corbyn talking about the problems of overcrowded trains.

“This is a problem that many passengers face every day, commuters and long-distance travellers. Today this train is completely ram-packed,” he said. Is it fair that I should upgrade my ticket whilst others who might not be able to afford such a luxury should have to sit on the floor? It’s their money I would be spending after all.”

Commentators quickly pointed out that he would not have been able to claim for a first-class upgrade, as expenses rules only permit standard-class travel. Also, campaign expenses cannot be claimed back from the taxpayer. 

Today, Virgin Trains released footage of the Labour leader walking past empty unreserved seats to film his video, which took half an hour, before walking back to take another unreserved seat.

"CCTV footage taken from the train on August 11 shows Mr Corbyn and his team walked past empty, unreserved seats in coach H before walking through the rest of the train to the far end, where his team sat on the floor and started filming.

"The same footage then shows Mr Corbyn returning to coach H and taking a seat there, with the help of the onboard crew, around 45 minutes into the journey and over two hours before the train reached Newcastle.

"Mr Corbyn’s team carried out their filming around 30 minutes into the journey. There were also additional empty seats on the train (the 11am departure from King’s Cross) which appear from CCTV to have been reserved but not taken, so they were also available for other passengers to sit on."

A Virgin spokesperson commented: “We have to take issue with the idea that Mr Corbyn wasn’t able to be seated on the service, as this clearly wasn’t the case.

A spokesman for the Corbyn campaign told BuzzFeed News that the footage was a “lie”, and that Corbyn had given up his seat for a woman to take his place, and that “other people” had also sat in the aisles.

Owen Smith, Corbyn's leadership rival, tried a joke:

But a passenger on the train supported Corbyn's version of events.

Both Virgin Trains and the Corbyn campaign have been contacted for further comment.

UPDATE 17:07

A spokesperson for the Jeremy for Labour campaign commented:

“When Jeremy boarded the train he was unable to find unreserved seats, so he sat with other passengers in the corridor who were also unable to find a seat. 

"Later in the journey, seats became available after a family were upgraded to first class, and Jeremy and the team he was travelling with were offered the seats by a very helpful member of staff.

"Passengers across Britain will have been in similar situations on overcrowded, expensive trains. That is why our policy to bring the trains back into public ownership, as part of a plan to rebuild and transform Britain, is so popular with passengers and rail workers.”

A few testimonies from passengers who had their photos taken with Corbyn on the floor can be found here