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  1. #1
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    Bottom Bracket Blues

    When I tighten the cup on my bottom bracket, there is about a 3/16” gap between the inner side of the ring on the cup and the frame. I have a spacer but it is only about 1/8” so I have an extra 1/16” that it can move around in. Does this mean I have the wrong width bottom bracket? Can I just get a 1/16” spacer from my LBS? I’ve ridden it this way and it seems fine, just came across it as I was taking the crank and cup off and cleaning them as I have a gritty sound when pedaling and I’m wondering if this slop is allowing grit in.

    thanks!
    chaz

  2. #2
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    Reputation: ghettocop's Avatar
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    This is an external BB? What is the shell width of your frame? 68 or 73? Is the 3/16th gap equal all the way around the shell or just in some areas?

  3. #3
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    Ah yes, it's coming back to me now, 73 without the spacer and 68 with. It is not an external, it is a first generation Superlight. The gap is equal around. So maybe I have some buggered threads and need to get my LBS to chase it?

    chaz

  4. #4
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    You say it's not external, but you don't tell us what kind of BB it actually is. I'm assuming that Superlight is the bike model?

    There are some ISIS BBs out there that rely on a rubber o-ring to take up the space between the frame and the NDS cup.

  5. #5
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    It is a 2001 Santa Cruz Superlight; ISIS BB that came on a Race Face crankset, I forget what model but it is several years old, maybe 4 or 5 years.

    chaz

  6. #6
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    I have an older Iron Horse that uses an Isis drive BB, Gigapipe SL. I just replaced mine and it came with an O-ring to take up the gap.
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    2011 Stump Jumper
    2005 Iron Horse Warrior

  7. #7
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    With a Race Face ISIS BB, a 68mm shell would have two 2.5mm spacers drive side and one 2.5mm spacer on the non drive side, a 73mm BB shell would just have one 2.5mm spacer on the drive side.
    I'm a member of NSMBA and IMBA Canada

  8. #8
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    ok, hauled it over to my LBS, mechanic took a quick glance at it and said the bottom bracket was screwed in too far. Correct install is to install bb part way, install the cup (and spacer if a 73mm) all the way in flush, then finish screwing in the bb, yes, with a little thread sticking out.

    chaz

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