A method of electro-dynamically matching a bearing assembly includes electrically separating inner and outer races from rolling elements of the bearing assembly with lubricant and rotating the inner race relative to the outer race. A voltage differential is applied across the inner and the outer races and via isolated rolling elements and the race eroded an electrical discharge event across a gap defined between the one or more of the races and rolling elements. Electro-dynamically matched bearing assemblies and reaction/momentum flywheel arrangements for artificial satellites are also described.