Abstract
Using flat-belt tire testbed this study investigated causal factors in the wear of tire tread. To ensure the success of the experiment the accuracy of the testing device was improved and the trial conditions were kept under close control. Measurement of the slip angles was refined to allow accuracy down to 1/100 degrees. Lateral movement of the belt, which causes variation in the slip angle, was reduced as much as possible. As a measure against sticky particles of worn rubber clinging to the surfaces of the safety walk ans tires a uniform amount of mica powder was electrostatically coated onto the tire tread surfaces. Surface whiteness was measured and controlled automatically to maintain a constant level. As the same time, tire tread surface temperatures were measured and automatically regulated by infra-red lamps, keeping temperatures constant. The amount of wear was calculated by weighing the tire, after drying them in a vacuum dryer, on a highly accurate six digit electrical balance sensitive down to 0.1g calibrations. Consequently, in a comparatively short time it was possible to ascertain measurable rates of wear as affected by a number of factors including: warm-up running, slip angle together with lateral forces, load, internal pressure, running speed and temperature. Utilizing the rates of wear measured for three types of tire, the lateral force frequency distribution when running on a certain road course was hypothesized, and the wear index calculated. It was found that the difference between tires varied according to the severity of the course (level of lateral force).
