A disk and spindle motor assembly of a rotating disk drive is constrained from freely rotating when not in use to reduce fretting of the spindle assembly bearings in the presence of vibration. Preferably, a small electric current is driven through at least one of the spindle motor drive coils to hold the spindle assembly in a fixed angular position while the disk drive is not in use. The spindle motor is preferably a brushless DC motor comprising a multi-phase electrically driven stator and a permanent magnet rotor. Drive transistors normally drive the different phases under control of a processor. To constrain the drive, at least one of the drive transistors for a phase is activated. The rotor is preferably rotated periodically to a different angular position by driving a different phase of the stator. The rotor is alternatively constrained by mechanical means. The exemplary environment is an on-board motor vehicle application.