Cerveloguy,
I just ordered some CH Aero Disk wheel covers. Figured for $60 it was worth the experiment. I also checked out Kraig Willet's site (not sure it was worth the $8, but what they hey). Interesting how the most important thing is just having some form of a disk covering the rear wheel. But the tests are done at 30mph where "few men/women go".
My question is how much do the hubs matter? I mean, I'm going to put the CH cover on my training wheels - ALX 320's (nothing fancy). How would this compare to Renn's hubs - or even Zipps? Are the hubs on the Renn, Zipp, or Hed top quality and this adds to the over all effect?
Especially at avg. speeds of around 20-23mph. it seems to me that the aero advantage of the disk is about the same regardless of what's on the bike, but the hubs would make a huge difference. I think a set of super quality hubs would add to the overall increase in performance too. Maybe that's why there are "race wheels" and "training wheels".
No one ever mentions hubs, just the aero benefit of the disk.
TheBikeRacer.com