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  1. #1
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    XTR Crankarm slipping when pedalling, possible to use no BB Spacer?

    Hi. I have a problem with my crankarm (non drive side) slipped out when i pedalled.

    When i check the crank shaft is halfway through. Is it possible for me to use only 1 bb spacer on the drive side and no bb spacer on the non drive side so that it bites the crank shaft.

    Im using BB90 Shimano.

  2. #2
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    Crank is toast.
    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  3. #3
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    Probably destroyed it, but a picture is worth a thousand words.

  4. #4
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    what is the width of your bottom bracket? if it's 73 mm, then yes. you should only be using one spacer on the drive side.

  5. #5
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    The BB spindle should be about 80% of the way through the non drive arm. If it was only half I wouldn't be surprised that it failed. I'd be picking up the phone to have a serious chat with whoever installed the crank. You might be able to get it back in action with some sleeve retaining compound, basically a heat sensitive glue, but that's going to be a crutch and last ditch effort.

  6. #6
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    Quote Originally Posted by customfab View Post
    The BB spindle should be about 80% of the way through the non drive arm. If it was only half I wouldn't be surprised that it failed. I'd be picking up the phone to have a serious chat with whoever installed the crank. You might be able to get it back in action with some sleeve retaining compound, basically a heat sensitive glue, but that's going to be a crutch and last ditch effort.
    Thanks for the reply. Yes im using 68/73mm BB with 2 spacers on drive side and no spacer on the non drive side. The picture is below.

    XTR Crankarm slipping when pedalling, possible to use no BB Spacer?-img-20130501-wa0031.jpg

    XTR Crankarm slipping when pedalling, possible to use no BB Spacer?-img-20130501-wa0027.jpg

  7. #7
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    What width bottom bracket she'll does that frame have? Looks like you have one spacer to many.

  8. #8
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    Quote Originally Posted by customfab View Post
    What width bottom bracket she'll does that frame have? Looks like you have one spacer to many.
    One, it looks more like two..

  9. #9
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    So its okay to have 1 spacer In drivetrain and no spacer on non drive train. Why is my shaft slipping? Before this same setup, could it be my cleats worn out? Using crankbrothers cleats.

  10. #10
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    Quote Originally Posted by Slapshock View Post
    So its okay to have 1 spacer In drivetrain and no spacer on non drive train. Why is my shaft slipping? Before this same setup, could it be my cleats worn out? Using crankbrothers cleats.
    Because you don't have enough of the splines of the spindle engaged with the arm. Simple. You have one (or two) spacers too many.

    Run as few spacers as you need to get the right chainline, not have your arms/rings nailing your chain-stays, and not have your crank-arm falling off

    Why would your pedal cleats have anything to do with this?
    Florence Nightingale's Stormtrooper

  11. #11
    the catalan connection
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    If youre lucky and only have ruined the left crankarm (Im just assuming, since its aluminum vs steel of the spindle) you can get a replacement of the left arm only. A lot cheaper than a whole crankset.
    "Blessed is the man who, having nothing to say, abstains from giving us wordly evidence of the fact." George Elliot

  12. #12
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    Quote Originally Posted by What&son View Post
    If youre lucky and only have ruined the left crankarm (Im just assuming, since its aluminum vs steel of the spindle) you can get a replacement of the left arm only. A lot cheaper than a whole crankset.
    Oh really. Where can i get that? Any website to reccomend. Im from singapore.

  13. #13
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    Quote Originally Posted by Slapshock View Post
    So its okay to have 1 spacer In drivetrain and no spacer on non drive train. Why is my shaft slipping? Before this same setup, could it be my cleats worn out? Using crankbrothers cleats.
    68mm BB's get 3 spacers, two on the drive and one on the non drive
    73mm BB's get 1 spacer on the drive side
    If you're using a E type FD, remove one spacer from the drive side.

    The BB spindle is long enough to accommodate all possible setups, you use the spacers to shim whatever shell your frame has to the maximum width. This isn't something that's open to interpretation.

    Since you brought up the thought of something else causing it are you sure the crank is slipping? Are the crank arms not 180 degrees apart? A slipping freehub or worn out chain/rings could cause a similar sensation.

  14. #14
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    Hi. Thanks for the response.

    Yeap the crankarms is slipping because it detached from the bike itself and stuck under my feet.

    I will try to remove all spacer today because im using avanti competitor 29 team frame the width of the bb tube is big. Will report today without using any spacer.

    XTR Crankarm slipping when pedalling, possible to use no BB Spacer?-screenshot_2013-05-03-08-17-28.png

    In case if this could be any of a help, above posted is my geometry and im using 68/73 SMBB90
    Last edited by Slapshock; 05-02-2013 at 06:20 PM.

  15. #15
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    Quote Originally Posted by Slapshock View Post
    Hi. Thanks for the response.

    Yeap the crankarms is slipping because it detached from the bike itself and stuck under my feet.

    I will try to remove all spacer today because im using avanti competitor 29 team frame the width of the bb tube is big. Will report today without using any spacer.



    In case if this could be any of a help, above posted is my geometry and im using 68/73 SMBB90
    I think this is the point that you need to take it to a competent mechanic. I get the feeling that you don't exactly understand what we're talking about and if you would like to salvage your gear it's time to bring in a professional.

  16. #16
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    Emmmmmmm

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