I finally gave up on the 'just tighten it more' approach to bottom brackets

Watched a guy at the shop yesterday strip a Shimano BB shell because he thought a little more torque would fix his creak. I've been turning wrenches since 2008, and I still see folks treat thread engagement like a suggestion. Why does everyone assume more force is the answer when most creaks come from dirt in the splines or a dry interface?

2 comments

2 Comments

hugo_gonzalez6824d ago

More torque" is usually someone trying to fix a tolerance issue with brute force. Most creaks are just the frame flexing at the BB shell, not the cups spinning.

david_stone24d ago

Actually @hugo_gonzalez68 I've got a different take on the BB30 creak issue. I worked on a buddy's Cannondale last month and the factory manual spec for that press-fit shell was only 15-20 Nm on the preload. After we cleaned the bore, greased the interface, and torqued it exactly to 18 Nm with a beam wrench, the creak was gone for good. The problem is most people torque the cups way past 30 Nm trying to stop the noise, but that just distorts the shell and makes things worse. Frame flex at the BB is real, sure, but a lot of times the sound is the cup moving against the carbon because the press fit was loose from day one. Getting the torque right and using the right retention compound has fixed way more bikes for me than just blaming the frame.