Influence of Wheel Bending Stiffness on Lateral Tire Characteristics

The tire is the only force-transmitting element between the road and the vehicle. Thus, the tire mainly determines the driving dynamic properties of a motor vehicle. The tire is connected to the wheel hub of the vehicle via the wheel. Therefore, the wheel is the first connecting element between the tire and the body of the vehicle. As a result, the wheel has an impact on the driving dynamic properties of a motor vehicle. Unlike the known requirements for a vehicle wheel such as durability, low weight to minimize unsprung masses, brake cooling and low mass moment of inertia for dynamic load changes, so far the wheel bending stiffness, is not the major focus as an influencing factor in vehicle dynamics development.

Nevertheless, the presented research reveals that the impact of wheel bending stiffness can have a significant influence on characteristic values such as cornering stiffness, aligning torque or high frequency behavior. Exemplary studies have shown that cornering stiffness can differ up to 5.3% between different wheel designs whereby the dimension of the wheels are the same. An approach will be presented, where measurement procedures and metrics for wheel bending stiffness are defined and state of the art lateral tire-wheel measurements on a MTS Flat-Trac and a static stiffness test rig are performed using different wheel designs. Ultimately, the goal of this study is to investigate and describe the dependency between wheel bending stiffness and the change in typical tire characteristics as well as to provide a virtual forecast for design and specification of wheels in the early phase of vehicle development process.