The picture shows the influence of velocity on the rolling resistance. The initially gradually rising characteristic of the rolling resistance coefficient, which rises progressively at a fluctuating speed range according to interpretation, is due to the superimposed effect of the the deformation wave on the flexion resistance. This effect increases with velocity.
In the case of H-type (up to 210 km/h (131 mph)) and V-type (up to 240 km/h (149 mph)) tires, the increased tyre rigidity attenuates the influence of the deformation wave formation. Thus the progressively rising phase of the rolling resistance begins at a higher speed and in a less noticeable way.
For computer simulations of rolling resistance, the dependence of rolling resistance on velocity can be approached by an investigation, which is obtained empirically while tyre-specific values are used for the constants C0, C1, and C2. For a reference speed of (62 mph), for a HR-type tyre the constants are approximately:
In summary, the following can be stated:
Apart from the external influences - velocity, wheel load, and tyre pressure, the rolling resistance depends on tyre design, materials and the rubber mixture used. Thus the radial ply tyre generally has a smaller rolling resistance compared the bias ply tyre. Moreover the tyre tread configuration has an influence on the rolling resistance. Small tread depths and a fine tread configuration reduce the resistance force while the compensating effect of the fine-structured tyre treads decreases with increasing speed.
The magnitudes of the individual components of resistance, i.e. flexing, frictional, and aerodynamic resistance cannot be precisely recorded by measurements. It can only be said with certainty that the flexing resistance forms the largest component of the rolling resistance. In order to measure the total rolling resistance, there are basically two different methods available. The road test has advantages from the point of view of a realistic road and basic conditions. It is however difficult to maintain the given test parameters as a result of external sources of disturbance such as weather conditions, non uniform or changing road surface, and traffic, all of which are necessary for reproducible tyre tests.