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Stop telling new mechanics to torque bottom brackets to the max spec
I keep hearing guys tell new hires to crank every bottom bracket to the high end of the torque range and it drives me nuts. 50 Nm on a threaded BB cup is not a goal to hit, it is a ceiling, and going there every single time is how you strip aluminum frames over a couple seasons. I have fixed 6 creaking bottom brackets in the past 4 months at my bench here in Reno and 4 of them were over-torqued, not loose, which nobody ever guesses. You chase the creak with more grease and more torque and you just make it worse because the cups are already biting into the shell. The spec range exists because bearings need a little room to sit right, not because tighter equals safer. Antisieze on the threads, snug it down, stop when it feels firm, and check it again after a week of riding. Anyone else seeing frames come in with chewed up BB shells from this, or is it just the riders I get around here?
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phoenix_thompson41mo ago
Who taught these guys that tighter means better? I ran a shop for 11 years and saw the same thing, BB shells all chewed to hell and the cups seized so bad we had to use a breaker bar to get them off. What gets me is the spec range is printed right on the cup or in the manual, and the top number is still safe, but only on steel frames with good threads and a face that is cut straight. On an aluminum shell that has been powder coated or never faced, 50 Nm will crush the paint and bite the threads every time. I always tell new guys to go to the low end, like 35 Nm, ride it, then check it. Nine times out of ten it never moves and the frame lives. The creak they are chasing is usually dry threads or a dirty face, not a loose cup, so all that extra torque does is make the next guy's job a nightmare.
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