We start off with premium high capacity bearings. You can tell immediately these bearings are more precisely made. They have less slop than other bearings and will take a higher load. All this adds up to the bearing spinning freer right out of the box, even before any treatment is applied. Now we add the RF85 treatment and wallah, you have one slippery bearing. We track tested these and after using them for a year, the bearing still looks like chrome. 4 High capacity bearings and races all treated with RF85. It will make a big improvement just changing the bearings, but changing the races also will add just a little bit more.