After your helmet, your skinsuit and your position, one last – but not least! – parameter comes into play in the quest for the smallest fictions: your tires. Which tires for which rolling coefficient? This is what we are going to explain in this article.
Your helmet matters!
Your head creates turbulence
In order to improve your aerodynamic efficiency, choosing the right helmet is essential and can save you up to 15 watts. When you are riding your bike, your head is exposed to the wind and creates significant aerodynamic turbulence because of its spherical shape.
Your helmet can reduce turbulence
To mitigate this effect it is important to smooth the airflow as much as possible behind your head and along your back. The time trial helmet is the way to give your head a more streamlined shape and to significantly reduce the drag behind it. In order to achieve this, it is important to adapt your helmet to your body shape and position.
Choosing the helmet that suits you is essential
The ideal helmet is specific to each person because it depends on factors such as the morphology of the cyclist, his inclination on the bike and the shape of his back among others. So how do you know which helmet is right for you? There is no secret other than testing, testing, and re-testing different models whenever you change your position.
Aeroscale helps you choose the helmet that fits your body
On the left is an example of a typical 30′ test session aiming at comparing 3 TT helmets, each one tested 3 times. The statistical distribution of the 3 tests is represented with a box blot chart. Most notably is that the dispersion of results is less than that of the average between the different helmets, allowing to conclude with a great confidence that the LAS helmet is in that case about 0.002m² (or 2W@43km/h) faster than the Giro, and about 0.006m² (or 6W@43km/h) faster than the POC helmet.
Does one helmet fit all bodies? The answer is clearly no!
One might think based on the chart above that the POC is not a fast helmet in general compared to the Giro helmet. However, such assertion is not true as the helmet choice is intrinsically correlated to the body shape.
On the right is an example of another rider who tested the Giro and POC helmet. In this case the POC – while being more instable than the other helmets – appeared to be the fastest one!
We strongly recommend to not consider blindly that because such pro rider or team uses a particular helmet, this means this helmet is for you. I personally did this mistake at a time when I was not able to perform precise aerodynamics tests. I switched to a helmet that looked very fancy and fast because many fast pro riders in the Tour de France used it. I now can precisely estimate that this choice costed me more than 10W and made me drop in all TT classifications…
Conclusion : a helmet needs to be chosen very wisely based on actual aerodynamic tests.
Can we go really faster on a bike without taking your position into account? Impossible! Let’s find out how your position influences the aerodynamic drag and why it needs to be tuned to optimize the aerodynamic coefficients.
Did you know that even your skinsuit allows you to optimize your performance on a bike? This is 100% due to aerodynamic drag. The weaker it is, the faster you go. Let’s discover more about it.
Choosing your helmet depends on multiple variables, including your morphology. In order to save your energy, it’s important to make the most efficient helmet choice to match your morphology. But first let’s try to understand why.