First, I have to admit that this session was gifted to me. It wasn’t something on my radar but a friend won an aero foundation session, unfortunately it wasn’t convenient for her to attend. So because of her incredible generosity I happened to find myself in the boardman performance centres wind tunnel.
That said, What did I learn?
Most painfully I learned that my beloved cycling cap is costing me speed. A whopping 3%! Or 9 Watts at 40km an hour... apparently, that was to be expected. It’s not just the peak of the cap causing drag, it disrupts the airflow over your helmet and back.
Interestingly I learned that my most aggressive position with hands on hoods, arms parallel to the ground was only fractionally less aero that all out in the drops low as I can go. What does this mean? I now know that I can rest my upper body on long solo efforts by switching between aero on hoods, to low on the drops without noticeably effecting aero resistance. Apart from when riding in cross winds, being in the drops caused far less drag than any other position. Which leads to..
More telling, was how affected we are by a cross wind. Getting low in a cross wind saves watts . We all think head winds hurt, but cross winds are pure evil.
What surprised me the most, was the difference that a change of position on the bike can make, without changing any of the settings on the bike.
The difference between my standard, hands on hoods, 90rpm, reasonably aero all day long position, and my most aggressive low down, hands in the drops position was a massive fifty Watts!!!
That means, all other things being equal I could change the required output to achieve 40kph on a flat course by up to 50 Watts just by shifting my position on my existing set up. That’s pretty incredible. Whether the most aero positions are practicable over the period of an hour? I don’t know... however it’s certainly something to dedicate time and effort to in training. Getting my body used to a more aero position will without doubt yield more speed than simply training harder. I’m not going to add 50 Watts to my FTP anytime soon...
Would I have thought to go?
Probably not, it’s by something I’m likely to have considered.
Would I go back?
Absolutely. After (hopefully) losing weight, getting narrower bars and a longer stem I’d be really keen to go back and see how those changes affect my drag, and predicted performance.