3. Deformable wheel kinematics

As shown in the previous section, the lateral deformation of the tire induces a behavior such that the wheel centers are no longer vertical to the center of the ground/tire contact patch. The kinematic consequence is that the velocity vector, relative to the ground, of the center of the contact patch is no longer carried by the ground trace of the rim plane. This is the manifestation of the drift phenomenon. A kinematic model that takes into account the tire's lateral offset (responsible for the drift phenomenon) is certainly conceivable, but the complexity involved is very great for an insignificant gain. It is generally accepted that the drift phenomenon requires at most two wheel revolutions. Since kinematic models do not take lateral offset into account, we have adopted a schematic in which drift is assumed to be established.