To improve and better understand tire wet grip mechanism, it is essential to perform test bench measurements under wet conditions. Analyzing for example different tread compounds concerning their force transmission potential, assume to maintain constant conditions and to monitor all changes during the test, such as the micro roughness of the track surface. As on public streets, on the inner drum test bench of the Karlsruhe Institute of Technology with increasing testing cycles we observe a drop in the friction level. This polishing effect on the test bench is found on artificial corundum surfaces as well as on real asphalt roadways.
When we perform wet measurements on our test bench, it is necessary to have knowledge about the grip level of the track surface in order to analyze the test results. For this purpose, we developed and build up a new measuring device called CFM-System (Continuous Friction Monitoring System). This measuring device was inspired by the GripTester from Findlay Irvine Ltd and allows fully automatic measurements in order to survey the friction level of the track surface. The measuring principle is a continuous braked 10 inches test tire whereby a longitudinal friction coefficient is determined. ... mehr