In a riding mower having a frame, a mower deck supported beneath the frame, a chair on said frame and a source of motive power also supported on said frame. The frame is supported on forward and rear wheel assemblies, and the wheel assemblies each have a supporting wheel, each wheel assembly having a vibration damping system interposed between the frame and each wheel assembly. The vibration damping system comprising at least one pillow interposed between the frame and each wheel assembly and each pillow being of a resilient material for absorbing shock and vibration resulting from a wheel contacting irregularities in the terrain traversed thereby.