Tire Rolling Loss and Pressure Increase

The laboratory practice of measuring tire rolling loss at constant, regulated pressure purposely deviates from in-service operations where the tire air is capped and the pressure varies with tire temperature. Nevertheless, even if the pressure is not allowed to change, the potential pressure increase between the initial (cold) and the equilibrium (hot) state of a tire can be estimated with the help of an equation developed from physical principles. Examples are given for passenger car, light truck, and heavy duty truck tires operated at constant speed but different loads and initial inflation pressures.