Originally Posted by
Eivind E
Seems like Nova just bump their bearing size up by a few tenths of a millimeter now and then to keep people away from 3rd party bearings..
I've been running a BTT with the 70% cheaper TKO bearing all day today and all day yesterday, and I felt like it worked fine.
If you really want to go crazy you can buy the ceramic $22 Protek bearing

The protek ceramics is what I use for rebuilds. Tolerances are nice and tight. For the price, well worth it even if it only lasts 4 gallon.