Accelerated Tire Wear under Controlled Conditions. I. Description of the Test System

Abstract

Abstract Tire wear is produced by a series of complex physical and chemical reactions occurring at the rubber-pavement interface. Because of this complexity a rather sophisticated test system is required to study this phenomenon. This paper describes such a system. It consists of an instrumented two wheeled trailer, a towing vehicle with appropriate control and recording instrumentation, and various supplementary measurement devices The conditions or factors that may be directly varied and controlled are tire slip angle and resulting cornering force, camber angle, load, and speed. Factors that may be controlled by suitable choice of test time and location are tire surface temperature and pavement texture. With this system, the three primary external factors that influence tire wear; tire force level, temperature, and pavement texture may be studied independently. This is in marked contrast to ordinary fleet tests where such factors are uncontrolled or mixed into a general matrix of conditions in unknown proportions. This independent factor variation is required for a realistic study of tire wear. The testing is done under accelerated conditions; sufficient losses are obtained in the range 50–500 miles depending upon the levels of the three primary factors. By appropriate choice of the levels of the three primary factors (mainly tire force) the rate of wear may be varied over a range of at least 50 to 1. The effects of tire load and speed on wear are, unlike their effects in ordinary vehicle use, due to the difference in tire force origin. In. trailer tests, the tire force is a sustained dynamic equilibrium force and is thus amenable to precise control. In vehicle use the forces are substantially transient and of an inertial character. The differences between these are pointed out. The system is completely described and operating procedures are outlined. A brief review of the basic factors involved in tire wear is given, including previous literature work on this topic.