This was his GP5000 comparison: Continental Grand Prix 5000 Comparison: 23, 25, 28, and 32 mm Compared Published: 2019-02-19 by Jarno Bierman
I just looked at the chart with a
15% drop and it appears that the
rolling resistance between a 25 and 28 is almost identical when the 25 is at 100 psi and the 28 at 90 psi (even though the Butyl tubes weighs 30 grams more on the larger tire)
Is this true... to me this means that you can pump up a 28 at less psi and it will have a similar RR to a 25 which will be at a higher psi.
I always thought that a thinner tire with high pressure would have less RR than a wider tire with a similar psi