How to save 10 watts and a lot of money by doing your own real-world aero testing

No wind tunnel, no problem: a quiet stretch of road, a free app and a scientific approach is all you need

Rider on a turbo trainer on a race track
(Image credit: Philip Sowels)

Why slog away on the turbo day after day if you can simply tuck in your head and pull in your shoulders to make just as big an improvement to your speed? OK, so it’s not quite that simple, but anyone with a bike, power meter and smartphone can do it.

To measure your aerodynamic efficiency, you need to work out your drag coefficient (CdA). The ‘Cd’ part refers to your coefficient of drag – basically your slipperiness through the air – while the ‘A’ refers to your frontal area. Multiplied together, these values tell us how much of our energy is being wasted on the wind. 

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Tom Epton
Freelance writer

Tom Epton is a freelance writer and data scientist. Originally training as a scientist after completing his studies in physics he realised that cycling was what he wanted to spend his life thinking about. Now he works with manufacturers, athletes and teams using cutting edge data science methods to find performance gains. Tom writes primarily about sport-science and tech!