A bearing assembly having a shaft member having a bearing race and a piezoelectric member opposing the bearing race is situated so that when a voltage is applied to it, it expands against the bearing race so that a preload of the bearing is varied. The assembly includes a rotor having two outer bearing races opposing the shaft's inner bearing races. The contact angle for the upper bearing races is different than for the lower bearing races. In one embodiment of the present system, the piezoelectric member is disposed between the shaft member and the bearing race for varying the radial position of the bearing race. In another embodiment, the piezoelectric member is disposed for varying the axial position of the bearing race. In one embodiment, the system includes a hydrodynamic bearing assembly having a stator member having a hydrodynamic surface and a rotor member having a surface facing the stator member hydrodynamic surface. A piezoelectric member is attached to either the stator member or the rotor member for varying the width of said gap between said surfaces.