Tire-Road Friction Measuring System — A Second Generation

The General Motors Proving Ground Model II Coefficient of Friction test vehicle is capable of measuring slipping as well as sliding tire-road braking friction properties. The design, system capabilities, operating features, transducing elements and data processing instrumentation are discussed along with the techniques used to verify system performance; typical percent slip versus brake torque coefficient data on various surfaces and conditions are included. Conclusions are drawn on the relative usefulness of a torque measuring device for measuring tire and/or road braking friction properties as a result of tire patch point relocation studies.