Considered the front alignment, a 4-DOF vehicle shimmy model with independent suspension was established by Lagrange equation. The numerical analysis for the speed range of multiple limit cycles and numerical characteristics was performed with respect to the change of the caster angle. It showed that the speed range of multiple limit cycles was advanced. The amplitude of unstable limit cycles was reduced. The amplitude of stable limit cycles was enlarged and the frequency didn’t change with increasing caster angle. The paper result was helpful to provide theoretical reference for reducing vehicle shimmy and controlling of multiple limit cycles.