The stock bearings are heavily greased and they also happen to be open or non-shielded bearings. The problem with the grease is that it is so thick it actually slows the bearings down and dirt also sticks to it which will cause the bearings to seize. So, the degreasing of the stock bearings provides to advantages: the bearings will spin much faster (your car will be faster) and, two, they will be much less likely to seize up.
Threaded Mode
