<div class="htmlview paragraph">The mathematical simulation of road vehicle dynamics under extreme or coupled conditions depends on an accurate tire modelling.</div> <div class="htmlview paragraph">The goal of this study was to develop a simple model taking into account the non linearities and the interactions between longitudinal, transverse and vertical forces in all conditions of road surface and velocity.</div> <div class="htmlview paragraph">The basic concepts are Coulomb's friction law, and the shear stresses between the road and the tire tread rubber, the tread being reduced to its equatorial line linked to the wheel rim by an elastic carcass. The behavior of the friction and elasticity coefficients is derived from experimental and simplified local models.</div> <div class="htmlview paragraph">A vehicle handling simulation program based on this tire model was developed by RENAULT.</div> <div class="htmlview paragraph">Some examples of calculations show the importance of the model for a realistic theoretical study of road vehicle handling.</div>