jens wrote:
Grand Prix TT clincher crr = .00337
Corsa Speed: clincher crr = .00273
Corsa Speed clincher crr = .00257 !! (On Zipp disk, 18-20c latex tube)
Vittoria Crono Tubular crr= 0030
tetonrider wrote:
Which version and width of the Crono?
Not so easy to find tubular that are <=20c any more (other than ones for the track), let alone 18c or 16c.
This is the Crono CS 20C. The one on my rear wheel actually measures 20.1; the one on the front only measures 19.4C. At least for my 808, you don't need anything narrower than this. That's the width of the brake track and the rim widens from there to 25.
tetonrider wrote:
Also, are the first two measurements with butyl tubes? And 23c clinchers?
All the clinchers were 23C, with 18-20c michelin latex tubes. I'm not sure why the Corsa Speed did so much better on my Zipp disk than it did on a standard rim. The wider rim I guess....
At this point, I'm going to use the 808 w/ crono CS tub for races with smoother roads and the Hed Jet 9+ w/Corsa Speed clincher for rougher road.
I'm betting that the 808 tubular is the best aerodynamically. Also with its smaller diameter I gain 0.75 cm drop on the front end with no loss of power. For the Jet 9+ clincher, the Corsa Speed rolls so much better, I doubt the aero cost will outweigh it -- particularly since it matches the rim width better than the TT does.
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