Minor unevennesses in the road are cushioned by the tyre and absorbed. Additionally the entire wheel moves relative to the vehicle structure over spring-and-damper elements. In this case kinetic energy is transformed into heat in the tyre as well as in the body damper. This means that the spring work regained for the movement when rebounding is smaller by a magnitude equal to the damping work when compared to the work done initially during compression. The figure provides an explanation by the simple example of a wheel without tyre.
Due to regained energy, the spring work does not have an effect on the wheel resistance, whereas the damper work ΔW relative to the covered distance constitutes the additional component of wheel resistance due to an uneven road FR uneven: