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  1. #1
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    Loose chain on new bike....

    So I just bought a Giant XTC Composite 1. 2x10 setup with shimano deore xt rear and slx front. The chain is pretty loose to the point where chain slap is prevelant. Going down dips the chain often slips to the left from the big to the small and off the chainring. I thought it might be gear combo at first but it happens in multiple gear combinations. It is so bad that the chain is hitting the bottom of the chainstay and cutting into the carbon....

    Wat can I do to alleviate this? Take out a link? My LBS is worried about shifting issues if I do. Is there any way to tell if my chain is too long?

    What about the rear deraileur? Is there any way to troubleshoot the tension to see if it is faulty?

    At the very least, is there any kind of bottom bracket/chainstay area bash guard that would work?

    Thanks for the insight.

  2. #2
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    That is a nice bike. I know that I had issues on my 2012 Carve dropping my chain (3X10). I bought the M786 RD and it is now fixed. That is the Clutched XT RD. However, for what you paid on your ride you should not have that issue. My issues was when I was in the 42/11 combo and riding fast and hitting bumps. My LBS said that it was the Front DR that needed adjustment to keep the chain from jumping. Might look at getting it checked out too.

    Mark
    2012 XXL Carve Expert

  3. #3
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    Thanks, I am definitely loving the bike so far. I know that chains can come loose depending on bumps and dips but it happens a lot. Second thought was gear combo but it happens regardless. I'll take it to my LBS and have them look at it.

  4. #4
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    Make sure your chain is the right length. It needs to be long enough when on your big chainring and biggest cog, plus 1 link. Remove any extras.

  5. #5
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    Is it 1 link or 2? Just looked at the Shimano tech manual and it says 2 links. Right now my chain is at 2 extra links.

    What about spring tension in the deraileur? Is there any way to test it to see if it is prematurely worn?

  6. #6
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    Quote Originally Posted by Caburtle View Post
    Is it 1 link or 2? Just looked at the Shimano tech manual and it says 2 links. Right now my chain is at 2 extra links.

    What about spring tension in the deraileur? Is there any way to test it to see if it is prematurely worn?
    One or two extra links shouldn't matter. I don't see how spring tension could be a problem on a new derailleur.

    It could be that you have the wrong derailleur cage length, although I don't see how Giant could screw that up on a new bike either. But sometimes shops swap parts on the bikes on the floor...

    As you shift into smaller gears, the derailleur cage "wraps" the extra chain that is not needed. A smaller cage can wrap less chain, so you can end up with a slack chain in smaller gear combos.

    You describe the problem as a slack chain, but there are many other reasons a chain would jump off the sprockets. Are you sure slackness is the problem?

  7. #7
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    Quote Originally Posted by smilinsteve View Post
    One or two extra links shouldn't matter. I don't see how spring tension could be a problem on a new derailleur.

    It could be that you have the wrong derailleur cage length, although I don't see how Giant could screw that up on a new bike either. But sometimes shops swap parts on the bikes on the floor...

    As you shift into smaller gears, the derailleur cage "wraps" the extra chain that is not needed. A smaller cage can wrap less chain, so you can end up with a slack chain in smaller gear combos.

    You describe the problem as a slack chain, but there are many other reasons a chain would jump off the sprockets. Are you sure slackness is the problem?
    I thought there might be a part mix up as well but the deraileur matches up with what is supposed to be there. It's the long cage non-clutch model.

    The front deraileur was adjusted today so we shall see how that effects tomorrow's ride. I compared the deraileur tension to other shimano and it was about the same.

    My main concern right now is the issue of the chain cutting away at the bottom of the chainstay. It is slowly eating into the carbon in a pattern that directly lines up with the chain when it is on the small ring. Did Giants engineering overlook this? I don't know, but I haven't heard anything else relating to this issue on other XTCs. I guess the next step will be frame skin.

  8. #8
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    Protecting your chainstay from chain slap is nothing new. Even for steel and aluminum bikes.

    Lizardstore

    Lizardstore

  9. #9
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    This is my first carbon bike so I was surprised how quickly the slap cut away at the carbon. I am very familiar with protectors on aluminum bikes. Thanks for help

  10. #10
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    Quote Originally Posted by Caburtle View Post
    Is it 1 link or 2? Just looked at the Shimano tech manual and it says 2 links. Right now my chain is at 2 extra links.

    What about spring tension in the deraileur? Is there any way to test it to see if it is prematurely worn?
    Park Tool Co. ParkTool Blog Chain Length Sizing

    It takes quite a while to wear out a derailleur spring, and even then it wouldn't be overly sloppy. You should wrap the hell out of the chainstay until you sort your problem out. Running one less link in the chain won't hurt anything unless you like to ride in cross-gearing (which you shouldn't do anyways), like big chainring + big cassette cog.

    The clutched Shimano derailleurs are supposed to help with this issue.

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