The day after I posted Aerodynamics Part 2 about some small and free or relatively cheap things you can do to reduce air resistance and drag I came across this video.
We’ve all heard that shaving your legs makes you faster. Does it? Check this out.
Over the 40 km length of their trial runs, differences in how hard the rider is going over relatively short periods of time may well be sufficient to account for the differences they observed and they don’t address how, or even whether, they controlled for differences in effort over the trials with and without leg hair. From what you can see in the video it seems pretty clear they didn’t use physiological measures to control for effort. Looking at the set-up in the video I would guess average speed was used as a control but without more information no hard conclusions can be drawn. However, the magnitude of the differences they observed certainly indicate shaving your legs is something worth exploring further if you want to reduce air resistance and drag.
Tuned In To Cycling 
Shaving legs is I believe purely about vanity. Look how defined I am. Back in the day of woolly clothing, long hair, loose clothing etc, do you think they were thinking about aerodynamics then. Pffff as if. We all say it is for that because to say it was for vanity may cast doubt on our masculinity…just a bit!
I think you’re right that vanity plays a role. But I think the main reason is that it’s a lot easier to deal with first aid and treatment of road rash after a crash when your legs are shaved.
Yeah I suppose there is that to, maybe that in fact is the main reason. Cheers…