Classic & Vintage - 70's Miyata w/cottered cranks -- bb threading?
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02-02-11, 12:13 PM
Hey gurus, I am fixing up an old junker Miyata -- orange women's road bike - stem shifters, cottered cranks, heavy, appears to have the frame tubes connected just by smashing tubes together (don't know what it's called, but not pretty, typical looking lugs or anything).
I plan to jerk the cottered cranks out and replace with a square taper crankset I have in the shed. Should I expect English or Italian/French threading on that old fixed cup? I'm going to make one of Sheldon's tools for the removal and just wondered.
Thanks for any help, I'll post pictures once I can.
02-02-11, 12:52 PM
just swap the spindles. Its likely not necessary to change the cups unless they are in bad shape.
02-02-11, 05:58 PM
Oh, I should have specified -- I'm not going to use a cup and cone with the old cups. I'm going to remove the entire bb and install a sealed cartridge unit. I didn't make that clear with my OP -- sorry about that.
I was just wondering about what a 70's miyata threading is likely to be before I start trying to wrench one way or another by trial and error ;).
02-02-11, 06:27 PM
i'd expect standard ISO/English threading. Most Japanese bikes used standardized stuff, even back then.
You can check the spindle for the number/letter code to get the BB shell width and spindle size. It'll be a 3, 5 or 7 followed by a letter.
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