Effects of Surface Curvature and Texture on Passenger Car Tire Noise Generation on Roadwheels and Roadways

Abstract

Differences in surface curvature and surface texture are the only possible explanations for the differences in the noise of passenger car tires measured on-road and on a laboratory roadwheel. To determine the individual effects of curvature and surface texture, acoustic intensity measurements were made alongside four passenger car tires operating on roadwheel and roadway surfaces as the two parameters were varied independently. In the study, curvature was varied by using roadwheels of varying diameters and a flat roadway. Surface texture was varied both on the roadwheels and on the roadway. The results show that differences in surface texture account for most of the differences observed between noise measured on-road and on a roadwheel. Curvature effects were found to be minor over the range investigated here (roadwheels with diameter greater than 1.7 m). It was also observed that another important parameter in causing differences is direction of tire rotation and measurement side of tire.