In this prior blog entry:
I described a comparison of the Crr data I had obtained using the regression method for five pairs of tire to the Crr values Al Morrison measured for the same tires in his well-known roller tests. Since that time, I have continued to collect additional data, and so thought it might be worth updating that prior report. Thus, without further ado:Figure 1. Crr of various tires measured on the road and on rollers.
Note that, except for the Continental Supersonic (SS) and Michelin Pro Race 2 SC data, where n=1, the field test results are averages based on 3-6 tests performed on separate days. The average (+/- SD) coefficient of variation across days was 7.9 +/- 2.8%.