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Chainset and BB Question

norrisnnorrisn Posts: 7
edited August 2016 in MTB workshop & tech

I have an old frame I am refurbishing and its shell size for BB is 73mm, now the chainset I have requires a BB to be 68 x 113.

Do I just get a 73mm x 113mm BB for the frame or because of the extra shell length do I remove the difference from the spindle length and go for a 73 x 108?

BBs are so confusing :(




  • whyamiherewhyamihere Posts: 7,677
    73x113. The shell width doesn't make any difference for the cranks, only the axle length.
  • norrisnnorrisn Posts: 7
    tried to fit the 68 one to the frame but it was a tight squeeze, think the threads might have gone in the frame. Could I fit a press fit BB in a threaded frame instead? trying to fix this bike on the cheap and dont really want to have to buy a whole new drivetrain.
  • HerdwickHerdwick Posts: 523
    no, you can not
    “I am a humanist, which means, in part, that I have tried to behave decently without expectations of rewards or punishments after I am dead.”
    ― Kurt Vonnegut
  • The RookieThe Rookie Posts: 27,811
    If it was tight it's more likely the threads are crudded up and need a clean out, if they were shot it would be loose.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • norrisnnorrisn Posts: 7
    Think youre right rookie, there was all types of grit and censored in the threads
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