Rocky M wrote:
Thanks everyone. I had the blackbox in there but getting new cranks & the shop said the race was toast. SUPPOSEDLY, they said I'm supposed to have the BB overhauled every 3 months with ceramic bearings. It's been at least 2 years since that BB was torn apart for any reason at all. Maybe 2x that.
I think your shop smells money. Ceramic bearings should require less maintenance, not more, than conventional steel bearings. Both the SRAM GXP and the GXP blackbox use sealed cartridges. So I'm not sure what there is to "overhaul" like there was back in the days of cup & cone bearings. With a GXP or blackbox it's useful to maybe pull the crank and wipe the dirt off of everything every three months or so, but that's a 5 minute job at home. I find it hard to believe your shop is proposing to pull the seals from the bearing cartridges, flush, clean, and re-lube everything.
As an earlier poster mentioned, friction facts reports will tell you whether the blackbox is faster or slower (hint: this is a possibility) than the regular GXP.
Finally, some have recommended wheels manufacturing ("WM") BBs, with one reason being "they thread together". WM makes excellent products, but if you're using a GXP BB already, that implies a threaded BB, and so the whole thing is already threaded. The WM solution to the problems of non-threaded BB's is to thread the two sides together themselves. This is perfect for BB30, and also useful for PF30 and BB90/BB86. However it's not an option (as it would be redundant) for threaded BB shells. If you are using a frame with a non-threaded BB shell, then my comment doesn't apply and the WM BBs are a great solution.