Everything we thought we knew about the aerodynamics of shaved legs is wrong
James Greig | September 9, 2014
Hairless legs are de rigueur for serious cyclists — whilst you might see the odd rider in the peloton sporting facial hair, you’ll never see one with hairy legs. It’s been this way for over a hundred years, and is now practically written in the rulebook.
The accepted reasoning goes like this: hair-less legs are easier to massage, and easier to care for if wounded in a crash.
And then of course, there’s the question of aerodynamics. (Usually raised by way of a wisecrack).
To the layman it seemed to make sense that having smooth body parts would result in a decent reduction in air resistance. But science told us otherwise:
The most widely cited test was a 1987 study for Bicycling magazine by engineering professor Chester Kyle, one of the pioneers of cycling aerodynamics. He found that leg-shaving reduced drag by 0.6 per cent, enough to save about 5 seconds over the course of one hour at the brisk speed of 37 kilometres per hour. At slower speeds, the savings would be less.
But now there’s new evidence to suggest that Professor Kyle’s results were way off the mark, courtesy of the new Specialized wind tunnel facilities in California, where American triathlete Jesse Thomas decided to investigate the effect his unshaven legs were having on his performance. The results caught everyone off guard…
The aerodynamicists in charge of the wind tunnel, Mark Cote and Chris Yu, were so surprised that they tested five more cyclists before they would let Thomas publicly reveal the findings. The results were consistent: All of them saved between 50 and 82 seconds over 40 kilometres.
So it seems that all that leg-shaving was worth it after all.
The only question now is what else needs to be kept hairless… arms… chins… where do we draw the line?
For further reading on aerodynamics, refer to Faster: The Obsession, Science and Luck Behind the World’s Fastest Cyclists.
I’ll leave you with the full video from the Specialized wind tunnel — jump to the two minute mark for the results.
Posted to London
by James Greig
