Originally Posted by
fly:yes/land:no
i would not deny the fact that the helmet companies are trying to make money by selling products, i would certainly not dismiss the idea that the shields can help if their is data or evidence to support it.
I spent a bit of time crunching the numbers of Tour de France ITT's since 1970. I excluded ITT's with serious climbs, but included prologues and split stages.
For 1970 to 1976, the average ITT winner's speed was 45.62kph. 1980 to 1989, 46.47kph. 1990 to 2000, 50.08kph. 2000 to 2010, 50.74kph.
As best I can determine, in 1991 Indurain used a metal round-tube frame, solid spoke and disc wheels, aero bars and an aero helmet. Indurain averaged 51.24kph on stage 21 (57km course) using a bike that probably weighed 25 pounds.
No one would be caught dead using a bike like that today. Yet in 2010, Cancellara averaged 51.15kph on Stage 19's 52km course. Wiggins averaged 50.16 on stage 20 (53.5km)
There was a big improvement in ITT times after 1989, i.e. after aerobars went into wider use. After that, the improvements in ITT's appear to have been extremely small -- despite vastly improved training techniques, users switching to power meters and power-based training, the switch to carbon fiber, carefully sculpted frames, internal cable routing, reductions in bike weight, greater attention to aerodynamics, significant reductions in overall Tour length and the rise of the "Tour specialists."
Obviously, teasing out one specific factor like "bike aerodynamics" from the various figures is very difficult, and I don't know if we would see the same thing for flat sprint stages. So I hesitate to draw too definite of a conclusion. But at the moment, yeah, I'm kinda skeptical.
