Originally Posted by
cobra_kai
Have you tested the crr of the compass tires vs continentals or just going by feel? Based on the roller testing data from Tom Anheult (
Blather 'bout Bikes) you are probably giving up around 15 watts to a pair of GP4000. I'm wondering if there is any data to support the 'fast rolling' claims of the compass or whether people are simply biased and regurgitating the company's claims.
Ha, interesting. I went by feel, of course. I got these tires mostly for long, fairly fast rail trail rides, where the wide tire with no tread would just float on top of the crushed stone surface. But they were surprisingly good on paved roads. It would be very interesting to get power numbers on rough chip-seal for the 23/25 tires and these 38 tires.
The Compass 38mm tire that's low on the chart is a knobby. My Barlow Pass EL 38mm tires are probably somewhere between the 44mm and the 35mm on the chart, so maybe 10w difference? The 44mm EL tires did very well, not much worse compared to the GP4000SII. (But the GP4000SII 25mm scored even better than this reference 23mm)
In the spring, maybe I'll swap tires and time some downhill coasts to see how much longer the big tires take.