Originally Posted by

**jur**
Regarding rolling resistance of small wheels, there are several aspects to consider:

1. The basic geometry consideration, that road bumps will slow a smaller wheel down more than a larger wheel, due to the fact that bumps have a bigger effect on a smaller wheel. Hence rolling resistance of an smaller, infinitely hard wheel is more.

2. But wheels are not infinitely hard, they are pneumatic. Road bike tires reach the optimum for typical road surfaces at about 110psi; anything more and the rolling resistance may actually increase because the tyre can no longer deform and smoothly roll over irregularities. So at this sort of pressure or slightly lower, the rolling resistance between the 2 sizes due to bumps become indistinguishable as the tyre effect dominates.

3. Due to the fact that a smaller wheel has a rounder contact patch compared to a bigger wheel, less of the tyre deforms, so resistance may actually be lower for the smaller wheel.

4. Put the smaller wheel on suspension, and bigger bumps begin to weigh in the small wheel's favour.

5. Aside from this, wind resistance dominates rolling resistance by a big margin.