We wish that bottom brackets wouldn’t get chewed up -- they seem so well-protected. Cranks, when adjusted right, never move laterally. Bottom bracket shells don’t flex. It’s hard to gaze admiringly at a bottom bracket, even when it’s new.

In dry conditions, dust gets into everything. In wet, water eventually carries dirt past seals and takes grease out when it subsides. There’s no escaping the damage that riding wreaks. The only out is not to ride. And we won’t let that happen.

So, you’ll eventually need to replace your bottom bracket. The Shimano XTR M970 Hollowtech II bottom bracket can replace any Shimano 50mm chainline bb. That includes all of Shimano’s MTB line, save the Saint 805 series cranks designed to work with the 150mm Saint rear hub. MSRP $59.99.