Monday, September 7, 2015

Getting Caught Up...

Yeah...I know...it's been about a year since I posted to this blog. Lots of "life" happening here.  Anyway, I recently had an unbelievable opportunity to "play" with Chris Yu and Cam Piper at the Specialized "Win Tunnel", and before getting into and (over?)analyzing the data from that adventure (we're talking wheel and tire combos, bare bikes, and even rider-on testing!), I thought it would be good to get my Crr spreadsheet up to date. I did test a few tires over the past year...not many...with the majority of what's been added being various flavors of Continental tires.

The spreadsheet linked to in the upper right corner of this blog page has had the following entries added:

Continental Supersonic 23C (New) = .0029, 27W for pair @ 40kph
Continental Attack 22C (~140 miles, "magic tire") = .0029, 27W for pair @ 40kph
Continental Force (used) = .0034, 32W for pair @ 40kph
Continental Attack 22C (ave. of 2 new) = .0036, 33W for pair @ 40kph
Continental Attack 22C (1 of 2 above, 118mi) = .0036, 33W for pair @ 40kph
Clement Strada LGG Gumwall 25C = .0045, 42W for pair @ 40kph
Kenda Kountach 25C = .0049, 45W for pair @ 40kph

So...a bit of discussion about those results above, especially in regards to the Attack models. As of now, I've tested a total of 4 Attack tires, with 3 of them being new and all of the new tires rolling ~the same at .0035-.0036. Even when taking one of those tires and putting ~120 miles on it, the Crr did not appear to change appreciably.  However, there was one Attack that was sent to me with what was claimed to have only ~140 miles on it...and that one rolled SIGNIFICANTLY faster at .0029. That's the one I call the "magic" tire. Knowing this, I would have to say that for anyone who wishes to run a Conti Attack as a TT/Tri tire, I would highly recommend roller testing the particular tire to make sure you have one of the lower Crr versions. For me, the majority of the Attack tires I've rolled have all been significantly slower. It might take quite a few tials...

The other interesting data point is the used Conti Force tire.  I had previously rolled another lightly used Force tire at .0029, as opposed to this particular one at .0034.  Again, like with the Attacks, it appears the Crr for these tires from Conti is highly variable.

The new 23C Continental Supersonic tested out at what I had previously estimated a new one would based on a well-used version I tested back in July of 2014, at .0029 vs. .0027. That ties it with the excellent Specialized S-Works Turbo Cotton 24C.

Well...that's about it for now.  The spreadsheet is updated with the tires I've tested in the past year.  Look for a couple of posts soon on my Specialized adventure!

4 comments:

  1. Hi Tom! May be rolled version save more watts because width is better! it's the same with my gp4000s 2 25 mm. In new version i have mesured at 25.5 mm width and 500 km latter 26.8 mm ! Happy to see you back !

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    1. That's why I took one of the 2 Attacks and rode around on it a bit. I do find that tires typically drop a point or 2 in Crr after "break-in", but in this case the Attack I used didn't come close to approaching the low Crr of the "magic" tire. Also, don't forget that a downside of tires widening with use is worsening aerodynamics.

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  2. Wonderful information. Is there a donate section? Also, the Tagente Speed 25 clincher has about the same Crr as the turbo cotton and is actually available. 4 watts faster than the Conti GP 4000 S in 23 which you measure as the same width as the Tagente 25. Any thoughts on the lack of a puncture barrier in the Tagente speed?

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  3. Seems like the aero/crit bottle goes pretty far in the gain/money invested ratio :)

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