Effect of Tread Design Changes on Tire Patch Dynamics at High Speeds Using a Dynamic Contact Force Measurement Rig

Abstract

The dynamic effects at the tire contact patch are one of the most difficult factors of a tire to measure. Generally, only the total forces at the tire axle are captured during the tests. There are a few methods for identifying the force distribution at the tire contact patch, but most of these methods are limited to static tests or dynamic tests at slow speeds under nonrepeatable conditions, such as with vehicle testing. Because of this limitation, A&D Company, Limited has developed a tire-testing machine called the dynamic contact force testing rig (DCFR) to measure the dynamic force distribution at the contact patch during high speeds and under reproducible conditions. Preliminary studies have shown that minute changes in shear stress and pressure distribution can be measured consistently. This study observes the dynamic force distribution in a high-performance tire under a variety of test conditions: varying normal load, speed, slip angle, and slip ratio. The tire tread was altered manually by siping additional longitudinal and lateral slits in the existing tread pattern. The tests were repeated for each tread pattern: stock tire tread, additional longitudinal slits, and additional lateral slits. The change in force distribution was compared along the longitudinal, lateral, and vertical axes. The results showed how small changes in tread design can influence tire performance. This article is a preliminary study, primarily investigating the capabilities of the DCFR while investigating basic observable trends in force distribution.