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  1. #1
    beerowulf
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    New question here. Spindle to Cartridge BB - Symmetrical equivalent?

    Hi all - questions about three vintage cup and cone BBs that I might convert to CartridgeBB, standard Shimano-isms, keeping the square taper cranks.

    The simple question, without all the background: Is the spindle length of a CartridgeBB, say Shimano UN54 or similar, equal length on drive side (DS) and non-drive side (NDS)?

    The background. I have three spindles I'm working with, a 3S, a 3T and a 3RR-B.

    Compliments of Sheldon Brown, an image at the bottomof the thread;

    The 3S is 121.5mm, 'A' the NDSide is 32mm, 'C' the DSide is 37mm - the symmetrical equivalent is 127mm.

    The 3T is 123mm, NDS is 32mm, DS is 39mm, SymmEq is 130mm.

    The 3RR is 136mm, NDS 42mm, DS 42mm, SymmEq is 136mm......

    The big problem is that few if any CartridgeBB spindles exceed 128mm, and if the A and C are equal lengths in the Cartridge BB, then I have to look at spindle lengths of a minimum of 127mm and longer, which is probably not happening...

    So to start - are Cartridge BB spindle lengths equal on each side?

    Thanks!

    dmc
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  2. #2
    mtbr member
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    To answer your question, the answer is NO. I just bought a 68x121mm BB and the drive side was longer than the non-drive side. I needed a 113mm BB which frm what I can tell is equal length on both sides

  3. #3
    beerowulf
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    Never gets simpler....hehe...

    Quote Originally Posted by was98strat
    To answer your question, the answer is NO. I just bought a 68x121mm BB and the drive side was longer than the non-drive side. I needed a 113mm BB which frm what I can tell is equal length on both sides
    Thanks was98strat - was going to bump the thread, but been busy.....

    Seems to me that DS and NDS specs would be the kind of info that suppliers should provide, but next to impossible to find....

    Just my .02, but seems to me that the shorter spindles tend to be symmetric and the longer tend to have a non-symmetrical longer DS

    That at least makes me hope that a 127mm Cartridge BBS will have a proportionately longer DS spec...

    Cheers

    dmc

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