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  1. #1
    Sofa King We Todd Did
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    About that rubber ring that comes with ISIS bottom brackets...

    I've installed about three different ISIS bottom brackets in past 12 months (all on different bikes). On two of the three installs, I've had a bit of trouble keeping that rubber ring on the non-drive side in place when I'm screwing in the cup. Only on one bike has that rubber ring stayed in place as I tighten the cup in as far as it goes. With the other two, I can tighten the cups 'til the rubber ring squeezes itself right out and pops off. So on the two bikes, I've tightened the cup in but not all the way.

    What am I doing wrong the two times the ring pops off? Is this an issue with the frame? Have I possibly used too much grease? What gives here?

    Many thanks in advance, folks.

  2. #2
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    Possible that those others were 73mm? I thought that rubber ring was to take up space when using the BB on a 68mm BB shell. Maybe those other two bikes are 73mm and you don't need to use the rubber ring.

    Of course if they were 73mm you sould be able to screw that side in all the way and not have any gap.

    I'm not claming to be an expert, I've only installed this type of BB twice. My Jamis is 68mm and has the rubber ring, my Yeti is 73mm and has no rubber ring.

  3. #3
    Sofa King We Todd Did
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    Cheers, mate.

    My ISIS bottom brackets have come with the rubber ring AND a metal spacer. According to the instructions, the spacer goes on the drive side and the rubber ring goes in the non-drive side. The last three bikes I put these bottom brackets on all had 68mm bottom bracket shells, so all I did was take out the metal spacer.

    In the absence of any more ideas, I might have to contact Truvativ directly for some advice.

  4. #4
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    Quote Originally Posted by SpinWheelz
    I've installed about three different ISIS bottom brackets in past 12 months (all on different bikes). On two of the three installs, I've had a bit of trouble keeping that rubber ring on the non-drive side in place when I'm screwing in the cup. Only on one bike has that rubber ring stayed in place as I tighten the cup in as far as it goes. With the other two, I can tighten the cups 'til the rubber ring squeezes itself right out and pops off. So on the two bikes, I've tightened the cup in but not all the way.

    What am I doing wrong the two times the ring pops off? Is this an issue with the frame? Have I possibly used too much grease? What gives here?
    Is it possible that you put too many spacers on the drive side?

    When I used ISIS BBs in my bike, the non-drive side cup never got close enough to the frame to put any serious amount of pressure on that rubber ring. In fact, when I was done, the rubber ring was usually still loose enough to be turned by hand. This had me concerned for a while, but then I realized that the non-drive side cup holds the BB cartridge in place by being wedged in between the cartridge and the shell.

    If you had put too many spacers on the drive side, the cartridge might not protrude quite far enough to be engaged (wedged) by the non-drive cup.

    That said, I don't think there's anything to worry about (aside from the fact that the chainline might be out a bit more than expected) so long as there's still a small gap between the non-drive side cup and the frame. If there isn't, I'd be concerned that the BB cartridge is not being held firmly by the non-drive side cup.

    Edit: After seeing your other post (in which you state that all three bikes have 68mm BB shells), it occurs to me that perhaps the shells were slightly wider than spec. If so, the use of the spacer would be correct, but might require the non-drive cup to be inserted far enough to see the problems that you referred to in your original post.
    Last edited by KevinB; 07-24-2006 at 02:28 PM.

  5. #5
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    Well as I recall, the BB is compatible with e-type front derailleurs. If you are not using a e-type front derailluer then you use the spacer. The spacer is not because of 68 / 73 mm.

  6. #6
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    Quote Originally Posted by oldskoolbiker
    Well as I recall, the BB is compatible with e-type front derailleurs. If you are not using a e-type front derailluer then you use the spacer. The spacer is not because of 68 / 73 mm.
    My recollection is slightly different.

    As you say, if you use an E-type derailleur (with a 68mm shell), you don't use a spacer. But if you have a 68mm shell and do not use an E-type derailleur, you do use a spacer. You never use a spacer with a 73mm shell.

    In other words, you need some type of spacer when installing the BB in a 68mm shell. The spacer will either the be space occupied by the E-type derailleur or the actual spacer that came with the BB.

  7. #7
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    that rubber ring

    Not sure if this helps, but I had questions about Truvativs little o ring way back when

    Truvativ Gigapipe SL BB install on KM

    The instructions said not to use it with the 73mm shell that my bike had, but also, the BB doesn't sit flush against the shell, so there was a space that looked about the size of the O-ring. I ended up just resting it around the shell/BB gap, then I eventually lost it.

    But I'm not sure it even has a function. Even though the instructions said there would be a gap between the shell and the BB, putting the O ring isn't really doing much. Grease or antiseize on the threads should keep the junk out.

    If on the one bike you have that it doesn't pop out, is the width of the space left for the o-ring about the same size as a spacer? If so, I wonder why they just don't tell you to use a spacer.

  8. #8
    *Hotter than Hell*
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    Quote Originally Posted by SpinWheelz
    Cheers, mate.

    My ISIS bottom brackets have come with the rubber ring AND a metal spacer. The last three bikes I put these bottom brackets on all had 68mm bottom bracket shells, so all I did was take out the metal spacer.
    Don't take out the spacer on 68mm BB. Look at the compatibility chart under the spacer and o-ring columns in this pdf.

    http://www.sram.com/_media/techdocs/...aPipe-e-r2.pdf

  9. #9
    Sofa King We Todd Did
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    Cheers, fellas. Some good advice all around. I did a bit more digging around and it turns out that your typical testosterone-driven stubbornness that made me go "Instructions? We don't need no stinkin' instructions!" made me install two out of my three ISIS bottom brackets incorrectly.

    The two where the rubber ring doesn't fit right have 73mm bottom bracket shells, not 68mm, like I earlier indicated. And when I read the instructions off the Truvativ site a little closer, it turns out that I need to toss out the metal spacer AND the rubber ring when installing into a 73mm bottom bracket shell.

    Glad that's cleared up now. I'll look to see if the cup does screw in flush to the frame or if there's a small gap.

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