AJS914 wrote:NovemberDave wrote:With a few caveats, yes, close enough.
So basically, nobody but a top pro needs to spend thousands on a set of carbon wheels because the 12 seconds over a 40k TT at 30mph is practically meaningless for the vast majority of riders - unless you are maybe Peter Sagan nipping Mark Cavendish on the line.
Well, I generally get chased around by people bearing pitchforks if I say that type of thing. I will say that that basic sentiment has strongly influenced a lot of my company's product decisions in the past year.
Wheel aerodynamics are not irrelevant but from what I see, people generally expect more benefit than is there to be had. If you take Zipp's example of their FC 808 saving 96 seconds over the benchmark aluminum wheel set in the 30mph 40k TT (link above), then you're going not quite 1mph faster with the 808s than you are with the benchmark. But remember that this is a worst to best comparison, and it's calculated at what's now accepted to be an unrealistic yaw angle which heavily favors the deeper wheel. Using the same methodology, a 404 makes you go about .75mph faster than the benchmark at wide yaw. Compared to a set of 101s, the 808s let you go about .4mph faster and the 404s are just under .25mph faster than a set of 101s.
But that's all at 30mph, at a maximized yaw angle that's wider than what data shows actually happens, and is in a TT environment with no drafting. Slow down to 25 (which is still very fast) and that decreases. Get in the draft and it cuts it by a third. And despite improvements in cross wind handling, the well shaped 30ish mm set is going to exert significantly less steering input in cross winds. And it can easily be at least 150g lighter than a mid-depth carbon and 300g lighter than deep carbon. At roughly 1/3 to 1/5 the price of major brand carbon. With more reliable braking. And no latex tube exclusions - which of itself alone can erase that aerodynamic gap.