Mechanism of Force Transmission Between Tire and Road

The paper presents a composite picture of current knowledge concerning characteristics and causes of friction between tire and road. The mechanisms that control development of friction forces in the contact area of a tire in rolling, driving, braking, and cornering, are related to sliding of a simple rubber block. In both cases, friction is due to a combination of adhesion and hysteresis. On dry, smooth surfaces adhesion predominates while hysteresis is principal factor on wavy, lubricated surfaces. Influence of normal pressure, sliding velocity, temperature, deformation frequency, and contamination on both friction components are dealt with. Conditions in contact area are analyzed and maximum coefficients obtainable in the several modes of operation are derived. Measures to improve frictional coupling between tire and pavement are outlined.