In this paper, a wheel-soil interaction model is detailed for estimating the forces within the contact surface. This model should take into account the mechanical behavior of both the wheel and the soil, considered in our work, as deformable bodies. The main objective is to ensure an accurate estimation of the contact forces for a better diagnosis of rollovers for all-terrain vehicles. Moreover, The wheel's sinking in the ground generates resistive forces that might influence the vehicle's dynamic. The global 16 degrees of freedom (DoF) model is, after that, presented and used as a basis for incorporating the contact model. Two scenarios are proposed to show the obtained results.