Coast Down Method in Time and Distance Variables for Tire Rolling Resistance Determination 2009-01-0072

An improvement of coast down method used for vehicle tire rolling resistance determination at drum benches is described.

The method is based on the discovered differential equation solution in form of explicit function “time-distance” for deceleration motion of mechanical system. This solution conforms with the partial solution of Rikkati equation [1]. It eliminates the traditional necessity to find values of the speed as parameter of indirect measuring which contains several sources of error. This simplifies required measurement instruments. A simple but highly accurate way of measuring the inertia moment of rotating bodies, free from the mass limitations, is proposed as an important part of the new method. It does not require a dismounting the rotating bodies and removing them from their supports. Examples showing the new method accuracy, repeatability and reproducibility are presented.