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  1. #1
    PS NOT STOLEN Mouton's Avatar
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    Bottom Bracket bearing size?

    I just found a square taper Shimano NJS bottom bracket today at a garage sale (thanks Judah!) The BB didnt come with bearings and so I ask you: Is there a standard for this sort of thing? 1/4"? All the rest of the measurements are in metric (68mmx107mm)so it seems weird that it would be imperial. Anyways thanx.
    -alex

  2. #2
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    99.99% chance that they're 1/4" AFAIK, there's no such thing as metric loose ball bearings on bikes. It's just one of those things that never got metricised.

  3. #3
    PS NOT STOLEN Mouton's Avatar
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    cool thanks. There are usually 11 bearings per side in a BB? that seems high.

  4. #4
    My Name is Joe jgsjr's Avatar
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    My Dura Ace hubs use 9, 1/4 bearings on each side.
    "It's all in the motor baby...if you got the motor then it really doesn't matter what you're shiftin'!" Andrea Ratkovic

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    Quote Originally Posted by Mouton
    cool thanks. There are usually 11 bearings per side in a BB? that seems high.
    General rule is a full race minus one. It's been too long since I repacked a loose bearing BB to comment on exact numbers

  6. #6
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    Quote Originally Posted by jgsjr
    My Dura Ace hubs use 9, 1/4 bearings on each side.
    He's asking about a BB.

  7. #7
    My Name is Joe jgsjr's Avatar
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    Well, a Dura Ace hub is metric like his BB and it uses 1/4 bearings.......
    The Dura Ace hub uses 9 bearings on each side and it is a bit smaller than a BB race so 11 bearings do not seem excessive.

    I think it is pretty relevant
    "It's all in the motor baby...if you got the motor then it really doesn't matter what you're shiftin'!" Andrea Ratkovic

  8. #8
    PS NOT STOLEN Mouton's Avatar
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    good point.

  9. #9
    PS NOT STOLEN Mouton's Avatar
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    For the record:

    11 25-grade 1/4" bearings on each side. Piece. Of. Cake.

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