They certainly seem like a clever way to get near disc wheel performance but aerodynamics can be weird. Are there any wind tunnel or road tests people have done to compare a wheel vs wheel + cover vs disc wheel?
OK the best I did was to compare two 10mile TT on a windy looped course. The first one was done without disk cover while the second one was done while fatigued (two days after an Oly distance tri) but with disk cover with weather conditions. The interesting fact was that my times were very similar BUT my NormPower was 15 watts lower on the second ride…
So I guess the disk cover to be worth 15 watts.
SteveMc
or you just coasted more and pushed a lil harder in other spots, as is very typical under fatigue
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do a search here for the link but there is wind tunnel data (supposedly—I haven’t seen it) that says the CH aero cover is just as fast as a Zipp disk. I think you need to pay $15 to see the results.
Anecdotally, I ride one (“cheap man’s disk”) and I think it’s very fast.
You might be right but this is the best answer I have to the given question. It is a pretty flat and exposed 2.5 mile loop. I’ve raced this course many many times, you don’t freewheel on it at all.
SteveMc
What were the avg watts of each effort? (As avg. speed has nothing to do with Np)
Kraig Willet tested an aero cover against a Zipp disc. You can get the results for this and a bunch of other tests for $14.95. Click on “projects”
Avg watts and NP are within 5 watts on this course for a 10 mile TT, sometimes even less. It’s flat and windy, you can stay in the aerobars the whole way round.
SteveMc