Originally Posted by
Fletcher
The center race is what is actually holding onto the shaft, the outer race is just riding around the outside on the actual ball bearings inside. If you beat on the outer race you are putting shock and force on the balls and the tracks they ride in. This can put little dents in the track or "race" which then interfere with the function of the bearing. Smooth road vs. bumpy road, one is better for your car, one isn't....
I hope that makes sense! <smile>