Rolling resistance is the energy that is lost when the tire is rolling. The main reason for the loss of energy is the constant deformation of the tire.

Each bicycle tire should, of course, roll as easily as possible. In contrast to a car a cyclist has only (very limited) physical power which he wants to apply as efficiently as possible.

In addition to the rolling resistance, there are also other resistances that must be overcome when riding a bicycle:

The air resistance rises in a squared ratio with increased speed. At a speed of approx. 20 km/h on level ground, air resistance has already become the main resistance force.

Acceleration energy is also expended. For instance, the weight of the wheels is of great importance when this mass has to be brought up to rotation.

When riding uphill, the main resistance force to be overcome is the gradient resistance (grade resistance).

In addition to these, there are other friction resistances in the chain and in other rotating parts. Yet in a well-serviced bicycle, these represent a very minor part of the total resistance.