Originally Posted by
CargoDane
That struck me as odd, so I clicked through and looked at the pressures they were running.
That test shows that the rolling resistance goes down only if the two tyres are at the same pressure. But that it goes up the wider you get if use the recommended pressure which results in a 15% drop of the tyre when loaded:
You lose about 1-1.5W of rolling resistance for dropping the tire pressure by 10psi. That's not going really significant, and as mentioned, you probably gain that back with reduced vibration losses.