Yeah black… Might need to go tan walls in the mean time!
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Cyclingnews has another article with more data from the Silverstone Pedaling Efficiency Rig. Lots of variables under test. Not sure what I think, yet.
https://www.cyclingnews.com/features...and-heres-why/](Lab tested: 40mm road tyres are faster for nearly everyone, and here's why | Cyclingnews
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got a summary for non subscribers?
Shouldn’t we be rewarding them with a subscription for this testing? It’s not cheap and they have been doing some good work with it recently.
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Their subscription fees are fairly reasonable and they good quality work. I’d respectfully suggest that you subscribe and check it for yourself
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Thanks for sharing. I can’t tell you what to think, but happy to answer questions if anything’s unclear.
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Looks like the zipp xlpr with a 32 is almost as fast as the hunt with the 26.
xlpr is hands down faster on cobbles and the bigger the tire the more watts you save.
Guess it’s time to pay for these CN tests hah
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Isn’t the XPLR rim only supposed to be compatible with 40mm and above ?
it is, they said its not recommended to run 32s with that rim, the 40 is less then 2 w slower then the 32 on the xplr wheel set @ 20mph and 6w slower at 25mph on tarmac.
Also the zipp is 15mm deeper. Kinda skews the data.
My take away from this is, if your running a 40mm tire, the zipp wins in everything. question is can you deal with 15mm more depth.
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SRAM/Zipp have a set list of approved tyres to use with those rims (Hookless Tire Compatibility | SRAM) and the P Zero we used isn’t on it. ETRTO’s guidance for a hookless rim that wide is a fair bit wider than 40mm (mid-50s from memory) hence SRAM tests and approves certain combinations.
For clarity, we tested the XPLR with 32, 35 and 40mm, but only in controlled environments. I value my teeth as much as the next guy!
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I’m not comfortable with such narrow tires on hookless. Even hooked I think that’s too much. These narrow tires don’t have tread wide enough to really lean over on or not get cut with so much sidewalk exposure
Yeah, i wouldnt ride anything less then 38 on the zipp wheel.
Great article / research Josh, well done and very interesting.
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Thank you for doing the test. Would be interesting to see gravel tires and mountain bike tires on those two rims in the same test.
What’s the wattage loss for inexplicable flats and sidewall gashes?
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Not sure. More people are running them
@joshcroxton I enjoyed the article. Is there any way to see a straight up CRR value from these tests?
The deltas seem to lineup with what I’ve done outdoors on cobbles.
Unfortunately not. With the way the pedalling efficiency rig works, it gives total system loss rather than crr. I tried reversing the equation too, but couldn’t get it to make sense. Was getting ~0.08, which was way too high.
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FWIW my outdoor cobble CRR values have been from .007 to .013 across 3 courses. Pretty high.
.08 would be wild.