In this example problem, the rigid rim is modeled with only one rigid surface, but you can model the rim with two rigid surfaces (one on each side) to be in contact with the 2D tire model. The motion of both rigid rim surfaces is governed independently via two separate pilot nodes. (Create the pilot nodes at the proper locations, as the reaction force/moment results on the pilot nodes give the net force/moment acting on the tire model.)

In the 2D axisymmetric tire model in this problem, the tire-rim contact pair is a frictionless contact pair, converted to a bonded contact pair after the model is converted to 3D. If needed, however, you can use a bonded tire-rim contact pair initially in the 2D axisymmetric tire model.

To resolve convergence issues (if any) due to the contact pairs in the 2D to 3D analysis, you can modify some contact settings. In this problem, for example, the pinball radius for the tire-rim contact pair is modified to avoid spurious high penetrations in the rebalancing step.

For the tire-road contact patch, use EEXTRUDE command options to obtain the desired mesh refinement in the hoop direction.

If you wish to include a nonaxisymmetric tread pattern, begin the tire-performance analysis with a 3D model and perform the rim mounting and inflation analyses on that model only.

The coefficient of friction for the tire-road contact pair should be ramped up in the first steady-state rolling analysis load step. You can define it either in the 2D axisymmetric tire model or during the 2D to 3D analysis process.

The allowable elastic slip (SLTO) real constant for the tire-road contact pair is a major factor in determining the free-rolling spin with desired accuracy. (See Using FKT, SLTO, and KEYOPT(13) in the Contact Technology Guide.) If the default SLTO value does not give the desired accuracy, try changing it.