Aero testing - is it really worth it?

The term “aero testing” has been banded around for some time now but it has so far always been reserved for those with unlimited budgets, namely professional athletes. As with all new technologies though, they eventually find their way to the mass market. There are now a variety of low(er) cost and easier to source aero testing facilities all aimed at making you go faster for less effort.

But, the crucial question is: Is it really worth it?  Will aero testing really make that much difference? Intrigued with all the social media posts around aero testing in wind tunnels and velodromes Coach Sorrel booked herself into a session and went to investigate further!

What is aero testing?

The aero testing session I attended was within a velodrome using a piece of software which measured my drag (CdA) in real time whilst I was on an indoor track.  CdA is a measurement of the frontal area (the A bit) and the drag coefficient of the shape of the frontal area (the Cd bit).  The lower your CdA, the more aerodynamic you are and the faster you can go for the same power output. The A part is me and my position, the Cd bit is how the air flows over me and how much of me it has to flow over – my "stickiness"...That's the very simplified explanation anyway!

The purpose of the session is to establish what equipment choices and position are best for each person.  We're all different, so just because Patrick Lange, Lucy Charles, or your riding buddy has a certain aero helmet doesn't mean it will be the best one for you.

It doesn't matter if you haven't ridden on a track before, although I have, as the Track Officer talks you through what you need to do. There is then a warm up period to get used to riding on the track

(which is huge amounts of fun in its own right and I would encourage anyone to go to a taster session!)


What happened?

Warming up/baseline data

After arriving and having a briefing with the Track Officer, I clipped in and rode around the track in my race trisuit and wearing my road helmet. I rode how I would ride during a race and this gathered all the baseline data needed as well as getting me warmed up and ready.  

Once the baseline data had been collected, I was then asked to ride with a slightly lower head position to gather more data.  Then came the fun part of trying different kit, first off - helmet swap.  

Now I am not against anything aero, but I am allergic to putting my hand in my pocket so am always cautious of getting the biggest bang for my buck.  The session itself isn't cheap but I was about to be converted. 

I tested out three different helmets, one of which I was told to take off after a couple of laps as it really wasn't working for me and was making me slower....which was interesting because in terms of looks and cost, it is one that I would have probably bought!

The helmet that gave me the greatest gains was the one I wore for the rest of the session.

My bike being modified

Time was then spent adjusting my position at the front end (I'd already mentioned that I was happy with my saddle position so the team were happy to not move that). I shared my session with another rider, so when they were out on track collecting data I was able to have the adjustments made to my bike and vice versa.   

Various positions were tested to gather as much information as possible to reduce the CdA without compromising on safety and comfort.


The results from my session were emailed to me and from that I was given a CdA value - and putting that data through Best Bike Split, it has given me some surprising results!

Remembering that it doesn't really matter what the number is, it just needs to get smaller:

  • My baseline (me just riding with my kit like I normally would) = 0.2739m2

  • With the better aero helmet = 0.2606m2

  • Changing hand positions = 0.2570m2

  • Adding a deep rim wheel and changing my front position = 0.2347m2

Data points collected through the session

It doesn't sound like a lot, but it actually equates to 20 minutes across a long distance triathlon bike leg.  I know this because we use Best Bike Split which analyses a course, the power output, the bike and now an actual CdA rather than an estimate.

This year I completed the Outlaw bike leg as a relay team in 6:06 - if I just move the data points for the CdA, then my predicted time is now 5:43. Even with just the aero helmet and changed position the time is still sub 6 hours (5:53).

20 mins?  I'll take that!

Now I know the session itself isn't the cheapest thing in the world, but if you think of it like a personal shopper then that wouldn't be too far from the truth.  If you're thinking of upgrading to some aero kit, isn't it worth making sure it is actually the right kit for you? The alternative would be always looking at different kit, wondering if it would be better than that which you currently have. For example, when I upgrade my wheels, I know exactly which ones I need to buy to make ME faster and which helmet suits MY riding style better.  And I only need to make a one time purchase.

With my allergy in mind, I am completely sold on what it is that I need to purchase - and I can do it in my own time, rather than when a marketing campaign tells me to. I know exactly what I need and can do my research to find the best deal.  

There are a number of companies out there that will do aero testing, a quick Google search should bring most of them up - if you're in the market for new kit and not sure what you need/want, then I would definitely suggest a visit to an aero testing session first. It may well be that you're in the best position and it's small tweaks you need and not a new £1000 disc wheel!

PS If you're thinking that this doesn't apply to you as you are a 'slower' rider, then think again!  As you're out on the course for longer, the gains add up more for you over time...need convincing? this...