Wheels both for passenger cars and trucks are one of the most safety critical parts on vehicles. Knowing this, in the 1970’s automotive industry started to rethink the design and also the lifetime assessment of wheels with respect to their different use case scenarios. Detailed measurements revealed the load influences from on- and off-road usage also including special and extreme load events. At that time, the BiAx or ZWARP test technology for rotating components of wheel ends were developed using these real life measurements to achieve a realistic fatigue assessment for any kind of wheel or hub in a lab environment.  

In the last years, the demands for the fatigue assessment have developed both with the variety of wheels and the usage itself. Especially, with regard to wheel and tire sizes as well as wheel test technology new demands from the customer side open up new research demands to assess the wheel’s strength. To detect the influences of fatigue test methods, the wheel and also the tire size intense fatigue investigations at Fraunhofer LBF were conducted. The aim was to derive the significances influencing the fatigue result and the parameters driving the fatigue assessment of hubs and wheels. The investigations showed that e.g. the tire ratio has a significant influence on the local loads on the wheel and thus the fatigue strength. This needs to be taken into account for the lifetime assessment and the fatigue test procedure to ensure a safe and reliable product.