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  1. #1
    Kid A TurbineBlade's Avatar
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    70's Miyata w/cottered cranks -- bb threading?

    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.
    Cyclist, angler and aquarist

  2. #2
    PanGalacticGargleBlaster Zaphod Beeblebrox's Avatar
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    just swap the spindles. Its likely not necessary to change the cups unless they are in bad shape.
    --Don't Panic.

  3. #3
    Kid A TurbineBlade's Avatar
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    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 .
    Cyclist, angler and aquarist

  4. #4
    PanGalacticGargleBlaster Zaphod Beeblebrox's Avatar
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    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.
    --Don't Panic.

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