The Weight Influence of In-Wheel Motor on Macpherson Suspension Hard Points

The integration of In-Wheel Motors (IWMs) in electric vehicles offers benefits in packaging, modularity, and control. However, the added unsprung mass may adversely affect suspension performance and ride quality. This study investigates the influence of IWMs on a MacPherson suspension, focusing on the behaviour of suspension hard points (HPs)‒the fixed locations that define geometry and affect kinematics. Two Altair MotionView models were used: one for a standard MacPherson system, and another with added IWM mass but identical HPs. A full Kinematics and Compliance (K&C) test suite, including ride, roll, lateral, braking, and steering scenarios, was performed. Results indicate that while HPs remain geometrically unchanged, the IWM-equipped system shows increased camber and toe variations, lateral displacement, and reduced alignment stability. These degrade ride comfort and handling. Thus, although existing HP layouts can house IWMs spatially, performance losses demand suspension re-optimization to preserve dynamic behaviour.