Technique

A beginner’s guide to aerodynamics – and why it’s so important to cycling

If you want to go fast, you need to understand aerodynamics. Here's are guide on why it's more important to evade than try and overpower the wind

Why aerodynamics matter

Every bit of kit these days seems to come with a claimed aero gain over a certain distance at a certain speed, but how much of that translates to the speed at which you ride?
Aerodynamics have become more an more prominent in cycling over the last few years, and are no longer just the domain of the time trialist
Whether your in the velodrome or on the road, aerodynamics are a key limiting factor in how quickly you'll be able to ride (pic: Alex Whitehead/SWpix)
No matter what, when you're riding on your own it's far more efficient to try and get out of the way of the air than attempt to overpower it
The best way to measure aerodynamics and the drag your produce as a rider is to test in a wind tunnel (pic: Endura)
Every bit of kit these days seems to come with a claimed aero gain over a certain distance at a certain speed, but how much of that translates to the speed at which you ride?
Aerodynamics have become more an more prominent in cycling over the last few years, and are no longer just the domain of the time trialist

Why aerodynamics matter

Why the recent obsession with aerodynamics? Well because they’re arguably the most important thing to worry about as a cyclist (alongside training, of course). We spoke to Dr David Marshall, aerodynamics expert and the wind tunnel manager at the University of Southampton, to get the low down on aerodynamics.

“Aerodynamics are fundamental in terms of performance cyclists, whether on the road or in the velodrome”, he explains. “Because of the way aerodynamic forces work, the drag experienced by the rider (that is the resistance due to the bike and rider passing through the air) increases with the square of the velocity it’s the case that a rider travelling at 50kph will experience four time the aerodynamic drag than the same rider in the same position travelling at 25kph.

“Taking that a step further, the power required to overcome this drag force increases with the cube of the velocity, and so our rider travelling at 50kph is having to put out eight times as much power as the rider travelling at 25kph.

“This is obviously a bit simplified, and it’s of course the case that a rider must also overcome friction in other ways such as rolling resistance and inefficiencies in the power transmission, but by far the largest force (at any reasonably velocity) will be due to aerodynamic drag. It should therefore be clear that, in order to use less power for a given velocity or go faster for the same power output, being ‘aero’ is the way to go.”