Optimization and re-design of a wheel hub to reduce unsprung mass of a rallycross car

Abstract: The Wheel Hub of a rallycross car is analysed to reduce the unsprung mass of the car. The problem statement is to mainly focus on the unsprung mass related to the suspension, and more specifically on the Wheel Hub. One of the objectives of the suspension system of a car is to damping the movement of the car. This is an important area when designing a vehicle, and especially a race car due to the extreme conditions that may result in reduced traction and loose of confidence for the driver. A theoretical model is performed to demonstrate the importance of a low unsprung mass and to illustrate how it affects the vehicle-handling. A process to evaluate the current Wheel Hub and decision to re-design the Wheel Hub is performed, and the parts are analysed using the Finite Element Method to verify the design and material selection. Vehicle dynamics of the car is analysed to calculate the acting forces. Optimization of the design is performed by using Computer Aided Engineering. The re-designed Wheel Hub presented as the result of this project with a Brake Disk Adapter integrated in Hub. This design reduces the number of parts, and the unsprung mass up to 25% without any effects on suspension geometry or other parts of the car.