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  1. #1
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    Spark 2013 and Xtr Incompatibility

    Hello my friends,

    I'm having a big problem with my new Scott Spark 900 RC 2013. I bought only the Frame and I bought a "Shimano XTR M985 Crankset 175mm, 30/42T" to use on it. The problem was that when i mounted it on the frame i realized that the space between the Outer rings (42 teeth) and the frame was too small, and due to the fact of being a Full Suspension frame, it was dangerously close to the rear part of the frame, with the risk of scratching and cracking the frame..
    Then trying to solve this, i changed the crankset for a Shimano "XTR M985 Crankset 175mm, 28/40T". I thought that 2 teeth less is going to be enought to clear the space between frame and crankset.
    But the last xc race that i raced, when i finished the race i realized that the 40T outer ring wasnt enought, the frame was scratched, check the photos, luckly it was not cracked.
    Im writing here to check if someone have a suggestion for me to solve this, I was thinking about:

    Option 1 - Use some BB spacers, but i dont know if i have space to use 2 spacers more. If i dont have space for spacers ill have to go with option 2.

    Option 2 - Buy a Shimano XTR M980 26/38T and replace my M985 Crankset. But i am using a Shimano XTR M986 Shadow Plus SGS 10sp Rear Der. (Long Cage) , with a 11-36 Xtr Cassete. I dont know if this LONG Cage Rear Der. is going to work nice with this new 26/38T Crankset. Can anyone please help me ?

    Photo of the scratches caused by the outer ring on the frame:


  2. #2
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    Could you get a picture shot downward from directly above.....those marks look like they also could be chain hangup so we need to see how far away the ring is. I doubt you'd get any more flex in that area than 1-2mm
    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  3. #3
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    Sure, here are more photos:




























  4. #4
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    Good photos!!

    The good news is that I can't see ANY way that the chainring is causing this. It looks like there is way too much clearance there for any small amount of chainring or pivot flex to make the marks.

    I've got the same marks as you, but mine are most certainly chain-related. Often caused by the chain hanging up on the large ring when switching down under power.
    Attached Thumbnails Attached Thumbnails Spark 2013 and Xtr Incompatibility-dsc_0548.jpg  

    Spark 2013 and Xtr Incompatibility-dsc_0549.jpg  

    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  5. #5
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    Thanks for the reply,
    Where did you bought that metal plate ? That is protecting your frame.

    Thanks,

    Eimart

  6. #6
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    That came with my bike (a Trek).....maybe there could be something aftermarket. You could look in the 'frame protection' part of online stores as a start.
    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  7. #7
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    Ive contacted the bike shop that build my bike and here is the answer:
    "Check that all bolt on the chainstay/seatstays are tight as you are flexing the frame too much. It does not seem that the chainrings are doing that."
    But i dont know if this is the problem

  8. #8
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    Guys,
    ive discovered something that i didnt realized before.
    I am using a XTR M985-E Front Derailleur, according to Shimano website it is for 40-44T Chainrings.
    I think that the correct one to use is the M985-E2, that according to shimano specs website is for 38T.
    Is it possible that this is the cause of the problem ??

    Thanks,

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