A disk drive is disclosed comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk. The spindle motor comprises a rotating component, a stationary component, and a first and second bearing assembly disposed between the rotating component and stationary component for rotating the rotating component about the stationary component, wherein the disk is attached to the rotating component. The bearing assemblies comprise a stationary component surface and a rotating component surface having a lubricant disposed there between. The first bearing assembly employs an anionic lubricant such that a first voltage forms between the stationary component surface and the rotating component surface when the rotating component rotates about the stationary component. The second bearing assembly employs a cationic lubricant such that a second voltage forms between the stationary component surface and the rotating component surface when the rotating component rotates about the stationary component. A polarity of the second voltage being opposite a polarity of the first voltage to thereby reduce the potential at the disk surface.