Tire grip significantly influences the minimum possible lap time of a race car. The potential of a race tire strongly depends on its thermal condition, the load distribution in its contact patch and its transient excitation, which is mainly determined by the variation of wheel load. At present, available tire models either disregard these complex relations or have them fully embedded without a possibility to trace its effects on the model’s results. Therefore the approach described in this paper uses a modular structure containing elementary blocks for thermodynamics, load distribution in the contact patch and transient excitation. Their outputs are utilized to get conclusive tire characteristics by adopting the fundamental parameters of a simple mathematical force description. This allows an isolated parameterization and examination of each block in order to subsequently analyze particular influences on the full model.

For the characterization of load distribution in the contact patch depending on inflation pressure, camber and the present force state, a mathematical description of measured pressure distribution is used. This affects the tire’s grip as well as the heat input to its surface and its casing. In order to determine the thermal condition of the tire, one dimensional partial differential equations at discrete rings over the tire width quantify the balance of energy. The resulting surface and rubber temperatures are used to determine the friction coefficient and stiffness of the rubber. The tire’s transient behavior is modeled by a state selective filtering which distinguishes between the dynamics of wheel load and slip.

Simulation results in the range of occurring states at dry conditions show a sufficient correlation between the tire model’s output and measured tire forces while requiring only a simplified and descriptive set of parameters. This allows a good assessment of the main influences of the tire’s state on its performance.