The Role of Tire Size Over the Fatigue Damage Accumulation in Vehicle Bodies

One of the most important components related to vehicle dynamics is the tire and wheel set. According to their dimensions (diameter, height, width, design) the vehicle dynamic behavior and driving comfort are seriously affected. Besides these aspects, the wheel/tire configuration has a main role over vehicle design and style. Nowadays, there is a design strategy which main feature is the increase of wheel diameter, causing the reduction of the tire side profile (tire height). After the increase of the wheel size, the total dynamic and static diameter of the whole set must be the same, causing the previous mentioned tire height reduction.In this work we investigate concerning the fatigue damage accumulation over light passenger vehicle body, related to the changes in the wheel/tire sizes. The vehicles were instrumented with strain gages in order to collect the stress levels acting at several areas of the vehicle body. These measurements were performed with a wide range of wheel/tire sizes in order to verify the importance of this component over structural integrity. The increase of the wheel size (and therefore decrease in tire height) has a significant role in the stress levels acting over the vehicle body, causing a higher fatigue damage accumulation. These new stress levels must be considered during the dimensioning of the vehicle components with higher wheel dimensions.