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Thread: BB sizing?

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    Newbie mjhickok's Avatar
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    BB sizing?

    So I took the bb off my 2012 Trek Wahoo. The label on the bb says 73x 122.5. I need to get a new power spline bb for it. Will I need to get a different size for the power spline?

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    Quote Originally Posted by mjhickok View Post
    So I took the bb off my 2012 Trek Wahoo. The label on the bb says 73x 122.5. I need to get a new power spline bb for it. Will I need to get a different size for the power spline?
    I assume (only an assumption, so best to measure) that the BB shell width is 73mm (mtn bike"), and the 122.5 might refer to the spindle length.

    If I'm right, the 73mm stays the same (part of the frame) and you have to get a BB made for that. But the spindle length may change according to the crankset's offset. Usually crank specs mention recommended spindle length someplace.
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    Andrew R Stewart Andrew R Stewart's Avatar
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    Power Spline... Are the arms' spindle holes still in good condition? I have to admit that the PS cranks I've had to deal with have been a disappointment in sourcing parts. Most have had rounded out crank arm/spindle holes. It's a shame that an orphan has survived in the market place for so long. Andy.

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