Science Focus - the home of BBC Science Focus Magazine
How fast could you cycle in a vacuum? © Getty Images

How fast could you cycle in a vacuum?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Bicycle bicycle bicycle… I want to ride my bicycle, I want to ride my bike, I want to ride my bicycle, I want to ride it where I like.

Asked by: Carol James, London


When you ride a bike normally, the wind resistance increases with the cube of your speed. At 32km/h, the power needed to overcome the drag accounts for more than 75 per cent of the total cycling effort, and this rises to over 80 per cent at 40km/h.

Recumbent bikes, which have much lower profiles to reduce their wind resistance, can already reach speeds of over 80km/h.

If you removed air drag completely, the only friction would be from the tyres and the bearings. Provided you had a high enough gear ratio to allow your legs to pedal at an efficient pace, you could probably reach well over 150km/h.

An easy way to simulate this would be to try pedalling on a stationary bike, but there are no published records for this sport.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.


luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


Sponsored content