Originally Posted by
asgelle
Except that article only considers one mechanism for rolling resistance. There is also energy loss from a tire bouncing on rough surfaces (as all real roads are). Above a certain pressure (usually around 120 psi) this grow faster than energy loss in the the rubber decreases. As a result further increases in pressure cause rolling resistance to rise.
And this has nothing to do with efficiency since efficiency makes no distinction for where energy is dissipated - heating air, heating rubber, or working against gravity.
Thank you for saving me from typing it all out.
Basically: Rolling resistance should decrease as pressure increases - only if you ride on glass roads. In the real world, rolling resistance is at a minimum at some pressure then only increases thereafter because the surface of the road is not perfectly smooth.