I have used the extreme tape and it is a bitch to remove a tire so I can’t believe that the tire is moving around on the rim.
The fact that the tufo was warmer after the run is interesting. I have said a few times that the extra watts must be converted into heat if they are not being converted into forward motion.
…the extra watts must be converted into heat if they are not being converted into forward motion.
And that is correct.
The theory is that tape or glue is a soft medium that does not return the energy it absorbs. Tufo tape, being quite a bit thicker than your average glue job, may make this worse. Several of the posts above reference some data (probably very old) comparing different glues. The Mastik 1 he used in the test above tested the best.
I wonder if the tester calibrated his speedometer for each change in tire pressure and each wheel. My Tufo Lites are slightly larger diameter than my clinchers when inflated hard, about 1%. Note that testing the same tire with increasing pressures and no speedometer changes, you should expect average indicated speed to go DOWN due to the increased effective wheel diameter, so an increase in speed at the same wattage is that much more significant. I’m assuming speed is taken from the power tap (rear) rather than the front wheel. I wonder if this difference in diameter is responsible for part of the bad rap Tufo’s are taking, espicially likely if you are comparing them when inflated to 200psi.
That is smart thinking. You can never take company claims on tire sizes. If I remember right, my 19c tufos measured 20 and the 21s measured 22. And of course, the tire width doesn’t tell the whole story. A 19c tubular will probably have a bigger overall diameter than a comparable clincher, but even that depends on the brand and how you put it on. The only way to know for sure is to do a rollout.
In my tests I sidestepped this whole issue, because I did timed runs over a course with a given start and endpoint – so the speed reading wasn’t needed.
– Jens
I was browsing the Continental site yesterday and noticed they mentioned using some sort of lubricant for the TdF time trials on their tires. I would suppose this is something that the casing absorbs? Anyone heard of such a thing?
Anybody try the Grand Prix Supersonic clinchers? They claim it to be the lowest rolling resistance clincher made. Intersting that they add “This featherweight tire offers exceptionally low rolling resistance that rivals that of Continental’s renowned tubulars.”
I maybe unlucky but if even look at my continental supersonics they puncture. I’m never risking another race on these.
edit: because I’m stupid thanks rmur.