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  1. #1
    amd
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    X9 chain line issues - gxp bb - chinese 29er

    I'm having some chain line issues with my chinese 29er where the chain wants to drop to the inside when the chain is on the smallest cog in the rear. Upon overhead inspection, I observed that the spindle for the X9 crank doesn't seat very closely to the bb itself, but has probably 3/4" space. Does the spindle flare out when it approaches the spider?

    I've only ever built road bikes where the spindle is a consistent diameter and the chainrings sit very closely to the frame. Here, the chainrings are quite a ways away from the frame, which I believe is causing a cross chain effect. It seems the chain wants to jump off more so when I spin the crank backwards than forwards, obviously not a big problem in real world riding, but it shouldn't happen anyway!

    Any advice on this?

  2. #2
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    Whats the BB shell width ?

  3. #3
    amd
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    not sure. its a sram gxp bb. I thought they were all the same width...

  4. #4
    Bro Mountainbiker
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    Grease your spindle and hit it with a rubber mallet on the center of the axle on the drive side. It should be sitting flush against the BB and sometimes they take a little bit of coaxing to get there.
    Raised in a Chicken-Coop by Chickens

  5. #5
    amd
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    ah. good to know. i'll try that. thanks.

  6. #6
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    have you seen this: X0 X9 X7 X5 Frame Fit Specs | SRAM

    Hope it helps.

    If the shell is 68mm you will need 2 x 2.5mm spacers to get the BB to the correct width,

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