Simulation and Investigation of Shimmy on a Light Truck Independent Front Suspension

The transient characteristics of tires can induce front wheel shimmy even on independent front suspension vehicles. Shimmy has been simulated using a front suspension ADAMS (Automatic Dynamic Analysis of Mechanical Systems) model after including the transient first order tire relaxation length effect. Shimmy was found to be sensitive to the steering system's natural frequency and damping, and the suspension caster trail. For suspensions with a low steering system natural frequency (below 12 Hertz), shimmy can be reduced or prevented by minimizing the caster trail and maximizing the system damping. For suspensions with a high steering system natural frequency, the rotating tire and wheel gyroscopic effects usually prevent shimmy.