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

How Jim Murphy's mistake cost Labour - and helped make Ruth Davidson

Scottish Labour's former leader's great mistake was to run away from Labour's Scottish referendum, not on it.

The strange revival of Conservative Scotland? Another poll from north of the border, this time from the Times and YouGov, shows the Tories experiencing a revival in Scotland, up to 28 per cent of the vote, enough to net seven extra seats from the SNP.

Adding to the Nationalists’ misery, according to the same poll, they would lose East Dunbartonshire to the Liberal Democrats, reducing their strength in the Commons to a still-formidable 47 seats.

It could be worse than the polls suggest, however. In the elections to the Scottish Parliament last year, parties which backed a No vote in the referendum did better in the first-past-the-post seats than the polls would have suggested – thanks to tactical voting by No voters, who backed whichever party had the best chance of beating the SNP.

The strategic insight of Ruth Davidson, the Conservative leader in Scotland, was to to recast her party as the loudest defender of the Union between Scotland and the rest of the United Kingdom. She has absorbed large chunks of that vote from the Liberal Democrats and Labour, but, paradoxically, at the Holyrood elections at least, the “Unionist coalition” she assembled helped those parties even though it cost the vote share.

The big thing to watch is not just where the parties of the Union make gains, but where they successfully form strong second-places against whoever the strongest pro-Union party is.

Davidson’s popularity and eye for a good photo opportunity – which came first is an interesting question – mean that the natural benefactor in most places will likely be the Tories.

But it could have been very different. The first politician to hit successfully upon the “last defender of the Union” routine was Ian Murray, the last Labour MP in Scotland, who squeezed both the  Liberal Democrat and Conservative vote in his seat of Edinburgh South.

His then-leader in Scotland, Jim Murphy, had a different idea. He fought the election in 2015 to the SNP’s left, with the slogan of “Whether you’re Yes, or No, the Tories have got to go”.  There were a couple of problems with that approach, as one  former staffer put it: “Firstly, the SNP weren’t going to put the Tories in, and everyone knew it. Secondly, no-one but us wanted to move on [from the referendum]”.

Then again under different leadership, this time under Kezia Dugdale, Scottish Labour once again fought a campaign explicitly to the left of the SNP, promising to increase taxation to blunt cuts devolved from Westminster, and an agnostic position on the referendum. Dugdale said she’d be open to voting to leave the United Kingdom if Britain left the European Union. Senior Scottish Labour figures flirted with the idea that the party might be neutral in a forthcoming election. Once again, the party tried to move on – but no-one else wanted to move on.

How different things might be if instead of running away from their referendum campaign, Jim Murphy had run towards it in 2015. 

Stephen Bush is special correspondent at the New Statesman. His daily briefing, Morning Call, provides a quick and essential guide to British politics.

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