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Found a 1980s Shimano tech manual that changed how I view bottom bracket threads
It was in a box of old catalogs from a shop that closed in '92, and it showed the original torque spec for a UN-55 was only 35 Nm, not the 50 everyone uses now. Anyone else run into old specs that make you question modern practices?
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mary7763mo ago
Totally get that feeling. Finding old specs like that makes you wonder what else we're doing wrong now. I've over-torqued plenty of bottom brackets following modern charts. Makes me trust the old engineers more sometimes.
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xena_brown503mo ago
Remember when torque wrenches were just a strong arm and the sound of a creak? Modern charts feel like they're written by people who've never actually put a bike together. I stripped a crank arm last year following the book and my old mechanic just laughed. Sometimes I wonder if they add extra numbers just to sell more tools.
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elizabethn562mo ago
Yeah, it's like the old specs were written for the metal they actually used. Now the charts feel like they're for some fantasy bike that never gets ridden. I bet some engineer just adds 15 Nm to everything so he can sleep at night. We're all out here crushing parts based on paperwork from a guy who probably never turned a wrench.
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