Hermes

ERO / Jim Manton is a great service for fitting and testing. My wife and I have over 12 hours of testing. It is different from tunnel testing in that one has to ride several laps per test to get a reliable result. The technology is a series of wifi sensors embedded under the track that collects speed and power data from the bike as on rides around the track. ERO has a mathematical model for the track that converts the live data to CdA instantaneously as one rides along the track that is diplayed on a laptop.

In general, it takes about 10 laps per test so a 200 lap session is pretty typical for a 3 hour testing session which is actually pretty hard on the athlete. Speeds do not have to be that fast but he likes a couple of fast laps per test since rider position can change for the better or worse at higher speeds.

When they announced the services a few years ago, we were beta testers for the service. The moment we heard about it, we were in. Over the years, ERO has serviced international and pro teams / individuals and has a large data base of human performance. So when one gets a fit by ERO, they know who is on the top of the pyramid with respect to equipment and positions. Interestingly, there are some trends where a certain position seems faster but there are athletes that are outliers such that one has to test and it is insufficient to assume that if tilting the aerobars up works for some it will work for all. It does not.

The downside of ERO is that they do not stock a lot of equipment so that one can test such as helmets. They may have a couple available so if an athlete wants to test a helmet, then one has to show up with the whatever they want to test and compare. To say it another way, one cannot test the five leading aero helmets against each other unless you show up with five helmets. For sponsored international and pro teams, this is not a problem. For amateurs with finite budgets, it limits what we can do in practice.

Last year, my wife did an aero test and for fun, we did a test where I rode behind her. My theory was that my pressure wave would interact with the disturbed air coming off her body and lower her CdA. The result was amazing. I lowered her CdA by 5% by riding behind her 6 inches from her wheel. So when we ride on the road and I ride behind her, we go fast for not a lot of power. The caveat is she has to ride in a perfectly strait line so that I can set up behind her for the wind conditions. If she is moving around a lot on the road, the effect is reduced.

Is ERO worth the cost? I like my own data and find discussion among and with racers / coaches very noisy. Somewhere within the noise are facts but it is impossible to differentiate what works for me. Testing allows me to stay ahead of the curve. YMMV