Using White Lake data to determine aero effeciency
About 8 EN members raced White Lake last weekend, probably most with power. The course is just about dead flat and we had the rare day with very little wind. So I got to thinking about this being a good opportunity to compare some power/speed numbers. This is about the perfect 56 mile course for that. So, heres what I did. I went to Analytic Cycling http://www.analyticcycling.com/ForcesSpeed_Page.html ; and put in my numers for Average power @177, my weight converted to kg, changed the slope to 0.0, and the road smoothness to .006. When I run the model, it says this should yield a speed on 21.3. My avg for the ride was 21.2, or 99.5% effeciency.
So if we all did that and put the numbers in a google doc spreadsheet or similiar, then what conclusions might be drawn from such a comparison? Since I have no way of determining frontal area, I used the default. Would differences in individual riders % effeciency coorelate well with their aero performance? Just seems like a good oportunity to look at some real results. I was running a HED Alps up front, a Wheel Covered rear, aero helment and stayed glued to the aero bars as much as possible. If anyone is interested in putting in their info, let me know and I'll set up a google doc.
Comments
I'm not a WSM, but I did the same ride. I rode at 21.3 mph, I weigh 168 and I had an Average Power of 198. So, I entered the data in that same Analytic Cycling and it said I should have ridden at 22.3 mph. So all I can figure is that I have a terribly non-aero position. This seems like a good problem to have because it should be relatively easy to solve. I think I will be contacting Todd at TTBikeFit. But I would also love any WSM thoughts too?
Similiar power analysis amongst several riders on the same course (Oceanside) and he determined that you should power up hills! Not sure I go along with the analysis, but here you go:
http://www.endurancecorner.com/Alan_Couzens/pacing_case_study
Food for thought.
Tom, interesting read. Kinda goes against everything we've been thinking doesn't it. But in a way, makes some sense on a course with rollers. As we've seen speed creates a exponentially greater aero drag requiring more power. Maybe working at FTP on shorter hills and recovering on the speedier sections would work if you knew the course well. Its interesting that my bike split on a rolling course, Augusta, versus a dead flat one, WL is almost the same with very similar AP numbers
we could do a "could vs. should" analysis of how predictive the analytic cycling calculator is, but I'm not sure how useful that will be, since we don't pace off of speed.
Seems to me that the most useful thing to do would be to do what John has done, which is to say "on that day, with my watts, weight, etc, I should have been going Xmph, and was actually going Ymph". The closer X is to Y, the more accurate your guess of the CdA is. Then, you can use that to decide how much effort to put into improving CdA...
Or, something else entirely could pop out after looking at the Google spreadsheet!
When I run my numbers it gives me 9.27m/s what the heck is that? meters??
@Dave, how do I get acces to "play along?"