Just to shed some light on the subject of bearings, there are some misconceptions about bearing numbers and what they mean. I would like to think that I have some knowledge on the subject being that my main business is bearings and seals, for my industrial company.

The bearings that come in these superchargers are C3 bearings. This C3 has nothing to do with quality or precision, it's just the internal clearance of the bearing. C3 is considered "standard fit". C2 or C1 is "tighter fit" while C4 is looser fit. That said, don't be fooled by someone saying C3 is a higher quality bearing, it has nothing to do with quality, just the internal clearance of the bearing.

There are also a million brands that manufacture bearings. Obviously, you do want to stay away from Chinese bearings, although there are some high quality Chinese factories that produce good bearings. Many of the Chinese factories have all state of the art new facilities, it's just the quality of the material that they use to manufacture that can be questionable. SKF is a brand that everyone thinks is an industry leader in bearing quality, however, you are really paying a higher price for the name rather than quality. ORS is a mfg. in Turkey that is 1/2 the price of SKF, but quality is top notch. They purchase all their steel from SKF Sweden, balls are from SKF Italy, and equipment is all from an old SKF plant. Another well known name is the German manufacturer FAG bearings. What many don't know is that most of their ball bearings are now manufactured in Korea by a company called KBC.

Basically, I'm just trying to let you guys know that we are knowledgable about bearings, and only would sell good quality bearings. All our kits use NTN bearings which are on par or better quality than the NSK bearings that actually come stock in the Eatons. They are also C3 fit which is also what come stock. Sorry for the long post but I hope this sheds some light on what's behind bearings.