Modeling Steady-State Suspension Kinematics and Vehicle Dynamics of Road Racing Cars - Part I: Theory and Methodology

This paper presents basic suspension kinematics & vehicle dynamics concepts along with the equations necessary to model the steady-state handling behavior of road racing cars on a personal computer. Definitions for roll center, the roll resistance contribution of springs & anti roll bars, and instantaneous motion ratios are refined. These refined definitions correct several assumptions present in the classic design methods which lead to erroneous modeling results. These design methods and modeling equations are valid for the unequal length non-parallel type passive suspensions commonly found in competition vehicles.

This paper is part one in a two part series. The second paper (SAE Paper #942506) includes the design specifications and modeling results for a CART Indy car, IMSA GTS car and two Formula Fords. The computer model used to study the handling behavior of these cars was created with the methods and equations described in part one.