Steering wheel vibrations are frequently related to non‐uniformities of the tire/wheel system. While steering system design is a major factor in the sensitivity of the vehicle, the excitation of steering wheel vibrations is due in general to non‐uniformities of the tire/wheel system. However, tire non‐uniformities are to some extent unavoidable and result in rolling force variation at the spindle during steady state rolling. Therefore, limiting and managing these non‐uniformities is of great economic importance to tire manufacturers.

The present work demonstrates the tire's role in generating non‐uniformity induced dynamic force variations due to 1st order geometric imperfections. Both analytical and numerical approaches are studied. Numerical experiments of the effects of non‐uniformities are investigated with the physics based tire model FTIRE. The effects of tire resonance on the non‐uniformity force amplitudes are demonstrated through modeling and simulation. The model is then verified using experimental data and the distribution of geometric non‐uniformities is studied in a large tire sample based on force measurement data and the model fit.

A MSC.ADAMS model of a light truck is combined with non‐uniform FTIRE models to study the effect of geometric non‐uniformities on steering wheel vibrations. The simulations show that the angular acceleration of the steering wheel around its steer‐axis is primarily dependent on force variations in the longitudinal direction (T1H). The effects of phasing, increase in inertia and tire position on the steering wheel vibrations are also discussed.

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