Braking performance of recent vehicle is controlled by the interaction between ABS system and the transmitted force between road and tire. Due to tire and suspension elasticity, an abrupt braking or the ABS regulation initiates tire belt and wheel axle oscillations, which leads to a closed loop of acceleration and force transmission in the tire-wheel-suspension assembly in both translational and rotational directions. As a result, the oscillation of wheel slip and wheel load can influence the force transmission potential in the contact patch and thus the braking distance as well. The objective of the presented study is to investigate the influence of the tire-wheel-suspension dynamics on the force transmission potential between tire and road.

In order to obtain acceleration and force dynamics in the tire-wheel-suspension assembly without inducing the influence from other vehicle components, a McPherson suspension was isolated from a real car and adapted to the inner drum test bench in Karlsruhe Institute of Technology (KIT), Institute of Vehicle System Technology. Mounting different tires, measurements haven been carried out under various driving conditions. First, tire measurements with a measuring hub were done on the test bench to obtain both quasistatic characteristics and dynamic response in rolling over cleat. Second, different tire-wheel-suspension assemblies have been driven on the test bench, while the wheel brake was initiated by a hydraulic braking system based on a modified ESP control unit. This modified unit allows generation of abrupt braking pressure slopes by a direct control of the valves. The accelerations of different wheel-suspension components and forces in the links have been measured.

In this paper, the experimental study of the dynamics of a Run Flat and a conventional tire and their respective coupled assembly with the suspension excited by rolling over cleat and abrupt braking is presented. After a description of the experimental setup, results of tire-wheel-suspension dynamics of two different tires will be analyzed, interpreted and compared. Finally, a simulation model of the tire-wheel-suspension assembly with FTire model will be build up and simulation results of force transmission potential in the contact patch will be shown.