Question about the torque spec on a common bottom bracket

I was putting together a new build yesterday and checked the manual for the Shimano BB-RS500. The spec for the left side cup is only 35 Nm... I always cranked those down way harder, thinking they needed to be super tight to stop creaking. Found it in the dealer manual PDF on their site. Has anyone else been over-torquing these and had issues, or is a little extra okay on this part?

2 comments

2 Comments

felix_perry67d ago

Used to crank that left cup down as hard as I could too... figured tighter meant quieter. Then I stripped the threads on a BB shell last year. Saw @bethh20's point about extra muscle, but that experience changed my mind. The 35 Nm spec is there for a reason, and going way over can actually damage the frame. A proper torque wrench and some good grease on the threads works better than just brute force.

bethh207d ago

Torque specs are just a suggestion for people who don't own a proper wrench. That left cup absolutely needs more muscle to stay put and not creak. A little extra is cheap insurance against a loose bottom bracket.