h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I know this is a bit off topic, but at a party a few days ago the discussion turned to the fact that (male) cyclists shave their legs, and the reasons for this.

The various theories were:
1. They like having shaved legs and so make up some nonsense as to why cyclists need to shave their legs.
2. It reduces wind resistance.
3. When you fall off, you lose significantly less skin if you've shaved your legs.

We felt 3 was the most believable, but I'd be very interested if anyone could add some facts to this debate. We were trying to persuade the keenest cyclist present to wax half a leg and then fall off a bike at speed, but he has no dedication to the advancement of human knowledge, and refused.

3 is partially correct.

*DD remembers his triathalon days*

However it also is supposedly having some minimal effect on wind resistance. How much over 7 hours in the Tour de France I'll never know.

Also in the event of a crash the hairs do not catch bits of dirt and let then seep into the wound if they aren't there.

i have a hard time believing that the amount of wind resistance leg hair causes is measaurable.

Depends how hairy you are.

That's why we didn't consider that theory credible.

I don't know anything about wind resistance but the girls on my high school swim team weren't allowed to shave their legs till sectionals. I was told that they worked with the resistance all season and shaved for sectionals to go faster.

Well, the whole point of our leg hair was/is to trap air so that you keep warm. And the wind resistance isn't so much impeding forward motion (that probably *is* minimal) as impeding the movement of the legs. That semi-trapped air also makes your legs heavier, which is again a bad thing.

Same reason why cycle shorts are marginally faster than normal shorts, really.

Theory 3 is the true one. When you drop it on tarmac the leg hairs tend to get trapped or melt with the friction and remove substantial quantities of leg hair.

Which hurts, A lot.