Performance Process: How to save 22 watts without a wind tunnel

A deep dive and a 101 on the process of aero testing at home.

Aerodynamics have taken over cycling in the past decade or two. From frames to wheels to clothing, riders can now aero-optimise every aspect of their ride. We also know aerodynamics are highly individual; a fast helmet for one rider might be slow for another. Despite the sport-wide uptake and understanding of aerodynamics, individual testing lags way behind.

In this week’s Performance Process, we talk to Escape Collective member, Notio Konect aero meter inventor/founder, and World Tour aero consultant Marc Graveline. Marc takes us on a DIY aero testing 101, breaking down the various options, testing protocols and essential tips for optimising at home.

Hear how Marc runs his tests, what to test, and how aero testing can on average save a rider 22 watts. Marc also breaks down to complexity that may present a hurdle to some aero-curious riders and explains how we can aero test at zero expense.

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Here are the time stamps for the episode and some highlights from a fascinating conversation:

5:31 – Average aero gains
9:20 – Aero testing options
12:17 – Finding the perfect location for aerodynamic testing
14:50 – Chung Method
20:47 – Testing with an aero meter
22:55 – Aero testing and power meter accuracy
34:56 – Aero Myths
37:55 – Ronan’s ridiculous aero-testing protocol
41:33 – Safety
46:56 – Common mistakes
58:34 – Consistency and data analysis
1:05:46 – Using power data to measure cycling performance
1:08:46 – Analysing cycling data from race performances
1:16:20 – Power meter accuracy and optimisation


Is aero testing too difficult?
“The main reason is probably the complexity, or the perceived complexity around aero testing. I think you have a large population of people that have tried it, and and didn’t succeed. And you have another chunk of people that heard of the first chunk, and then said, ‘Well, if he wasn’t able to do it, I’m not going to be able to do it.’ And then there’s probably a chunk of people that don’t believe that they can gain that much from it. So they’re very sceptical. They think the way to get aero-optimised is to post some pictures on a Facebook page and take people’s input, and they’ll be optimised that way. So I think there’s probably people in all three camps. And there’s the people that just don’t care. They do it (cycle) for fun, and they’re not competitive. But I’d say overall, I think the complexity of aero testing, or the perceived complexity is probably what holds a lot of people back.”

Testing with an aero meter
“In my case, we were testing Sylvan (Adams), and when I test people, in general, we’re using an aero sensor, and therefore we don’t care about constant wind, it can be as gusty as it wants to be, we don’t care about that, because we’re able to measure wind. So that’s a bit of an unfair advantage to the first person that doesn’t have an aero metre. Same thing for altitude: we have a very accurate inclination measurement system. So we don’t force people to do an up-and-down or an out-and-back type of thing. So it depends what equipment you have. That will dictate, how limited (is) the protocol and venues. The ultimate solution is you just go out on the road, you just ride for three hours. And you can do 10 tests here and there as you’re going along with no protocol and no worry about other things. But that requires more equipment, which isn’t at the disposal of the average cyclist. That’s exactly what I do. So I say that every ride that I do is an aero test, and most of them are also workouts, so I do most of my aero testing while doing workouts and vice versa.”

Aero myths
“You know, the most frustrating part about the whole aero thing are the aero myths. People say this and that, and we tested Lionel (Sanders) recently, and he put on one of the POC Tempor helmets, and I must have received like 200 messages. ‘Well, that helmet is no good if you move your head,’ and well, okay, the reality is it was faster for him. And trust me Lionel moves around. And he said to me, ‘Even if it isn’t faster, if it’s the same, it’s cooler, (has) better vision, quieter, a whole bunch of things,’ but the amount of messages that I got: ‘No way should he be testing with his helmet we should be using this helmet,’ it was funny. It’s all the aero myths.”

On Safety
“Safety first. I test on a road with logging trucks. And maybe a kind of public service announcement, everybody get a Garmin Varia when aero testing. So that you know when cars are coming up behind you and you can scoot over to the side, and you know when you can safely ride more in the middle of the road.”

Common testing mistakes
“One very common mistake is people try to do too much in one session. So they want to test, say, nine things. And they can only do 13 test runs. Therefore, they do one test run for everything, and they can’t really figure out standard deviations or errors or whatever. So, I would have a tendency to say, until you get really good at this, until you trust the equipment you’re using, until you trust your protocols, test a little less, and do more repeat runs to ABBA, rather than trying to go from A to P. I’d say repeat, repeats, repeats, repeats, repeats till you get better at it.”

All that’s left to say is, go forth and aero test, dear reader. And don’t forget, we have much more over on the whole Escape Collective podcast network.

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