Research quantifies advantage of riding in a peloton during bicycle races

It's only a few days before Chris Froome, Mark Cavendish, Andre Greipel and their hundreds of teammates and rivals set off on the world's most famous bicycle race, the Tour de France – three weeks of zipping through the French countryside, up and down mountains and through cities and towns, accompanied by a huge publicity circus and, no doubt, much depressing controversy about cheating. It's an event which is famously difficult for newcomers to follow. Why do the cyclists tend to ride in a huge bunch, known as a peloton? Why does the peloton so often catch up with cyclists who try to break away from the group?

The answer is the wind. Travelling at high speeds, cyclists experience wind resistance even in the still air, and with three weeks of riding and exertion, they will do anything they can to reduce their exertion. Riding in a bunch means that only the riders at the very front "break" the wind, as the unfortunate expression goes, and everybody behind them is sheltered.