Here are some photos. Hmm. sometimes, I wonder if I don't give away too much. 12 years ago, I was the only one gluing race numbers on. Now, everybody does it. If not for me taking the mickey out of Tufos, my competitors might still be riding them and losing 20 watts. Anyhow, here's the Roval with Corsa Speed and the Jet+ with SS 20C. See notes below.

I couldn't believe how easy it was to pop the Corsa Speed onto the Roval. No tools at all. I didn't even lose skin from my thumbs. Forget 20%. It's now 40%

On the Roval, the Corsa Speed measures around 26.4, just bit less than on the Hed. But the Roval is a much wider rim, so the tire should easily fall within the 105% rule (it's over that on the Hed).

On the Hed, the SS 20C measures 24.85. That puts it well below the inflection point of 26 and well with 105%. Is it too narrow for this rim? Just eyeballing it, I don't think so.

So I'm not even sure which of these two I should use in my next race. I do know that the Hed Jet+ under-performed my old 808 with the 20C Crono in my last two races. So I suspect it has an aero problem.

Did you use a bit of soapy water as lubricant for the install?

Well here it is. I only did one run on each tire. So I may do more in the future. All tires were inflated to 110 psi this time.

Supersonic 23C: .00292 (on generic Powertap wheel with 18-20c michelin latex tube)
Supersonic 20C: .00282 (on generic Powertap wheel with 18-20c michelin latex tube)
Corsa Speed: .00276 (on generic Powertap wheel with 18-20c michelin latex tube)
Corsa Speed: .00255 (on Zipp Super 9 disc)
Corsa Speed: .00319 (!! on Hed Jet+ disk -- same tire as used above, but with Vittoria Latex tube)
Crono tubular: .00292 (on 808)

So the preliminary result is that the SS 20C actually rolls a little faster. No surprise, since it feels thinner than the 23C version of the same tire. Are all the 20Cs like this or is it just Conti mfg inconsistency? Who knows?

The other tires were consistent with previous results, except the Corsa Speed on the Hed disk. This tire was an absolute nightmare to install. When it finally was on and inflated, I noticed that for about 10cm of the diameter, the grey sidewall was below the rim. I noticed the effect immediately on the rollers, where I got a really bumpy ride: ka-bump, ka-bump, ka-bump. Deflating and reflating failed to fix it. From the imprint on the tube, it appears that the tube may have been twisted inside the tire. The lesson is: installation matters!

I haven't seen this posted on ST yet. Another data point for Supersonice comparison. Interesting on the tire weight of the sample tested. http://www.bicyclerollingresistance.com/...prix-supersonic-2017

I haven't seen this posted on ST yet. Another data point for Supersonice comparison. Interesting on the tire weight of the sample tested. http://www.bicyclerollingresistance.com/...prix-supersonic-2017

I think that 180g is actually typical of the 2017 GPSS 23mm. I have some in the 190g range. They changed the tire, making it wider and heavier, and didn't bother updating the published spec. It also seems to not roll as well as the older version.

Yeah, so might as well use the GP TT unless you can get the earlier version of the SS.

What I don't like about that site is that they tested a 25 mm TT and are comparing it to a 23 mm SS. There's no testing of the 23 mm TT. Not exactly apples to apples.