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  1. #1
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    Which BB for my Shimano XTR

    Hi All
    I am getting a 2010 Epic Comp Carbon soonish.
    According to the spec sheet it has a 'Custom Shimano BB-91, OS, press-in bearing'.
    If I were to upgrade to the new Shimano XTR 2x10 speed, how would this effect my BB installation, would I need to replace, does the BB that comes with the XTR differ?
    What should I be prepared for, if I want to do this upgrade?

  2. #2
    Former Bike Wrench
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    An XTR should be a direct fit in the existing BB on the bike.

  3. #3
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    The BB-91 is press fit where the std BB that comes with XTR crank-set is threaded in. I think it's called Type 86 BB. Other than the way its fixed into the frame everything is the same.

  4. #4
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    Excuse my dumb question, but if one is pressfit and the other threaded, how do both go into the same hole?

  5. #5
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    Quote Originally Posted by philman
    Excuse my dumb question, but if one is pressfit and the other threaded, how do both go into the same hole?
    I think they mean use the existing bb with xtr cranks.

  6. #6
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    Quote Originally Posted by Q dog
    I think they mean use the existing bb with xtr cranks.
    Thanks for clearing that up, I now understand.
    The BB in place should fit the new XTR and not need replacing.

  7. #7
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    The frames BB shell doesn't have any threads and the BB cups don't have threads and the cup and bearing is press fit....like a headset.

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