A high speed flywheel system for a vehicle, i.e. capable of running at speeds of 20,000 rpm or greater, the system comprising a flywheel mounted on a shaft and contained within a housing, and at least one bearing arrangement, wherein the bearing arrangement is mounted to the flywheel or the housing via an elastomeric component such as a ring and/or a metalastic bush, thereby to reduce NVH and prevent the resonant modes of the flywheel and housing interfering with one another.