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  1. #1
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    Chain drop only in low gear

    I've been having a weird issue where if I put the bike in the lowest gear (highest cog in the rear) the chain has a hard time staying on the big ring in the front. There is no front derailleur rub either. I can replicate it on the stand by holding the rear brake and pushing on the pedals. If I push hard enough I can actually make the crank slip. It's a KMC X10SL chain, XX crank, XO cassette. Are the KMC chains directional? Do I have it on backwards? It's not an old chain, but the frame is new. I pulled all my components off my old bike and put them on here. It's a Niner Air 9 RDO.

  2. #2
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by Alexgonzalezmi View Post
    I've been having a weird issue where if I put the bike in the lowest gear (highest cog in the rear) the chain has a hard time staying on the big ring in the front. There is no front derailleur rub either. I can replicate it on the stand by holding the rear brake and pushing on the pedals. If I push hard enough I can actually make the crank slip. It's a KMC X10SL chain, XX crank, XO cassette. Are the KMC chains directional? Do I have it on backwards? It's not an old chain, but the frame is new. I pulled all my components off my old bike and put them on here. It's a Niner Air 9 RDO.
    You should not use the big-big combo. Poor chainline, high wear, low efficiency, and drops off the ring easily
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  3. #3
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    Apparently the chainring is smoked. I put a different chainring on and it works fine. The only problem is that its a 42t XX on a Air 9 RDO which isn't recommended.

  4. #4
    Nouveau Retrogrouch SuperModerator
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    Quote Originally Posted by Alexgonzalezmi View Post
    Apparently the chainring is smoked. I put a different chainring on and it works fine. The only problem is that its a 42t XX on a Air 9 RDO which isn't recommended.
    The poor chainline is still a factor and the chain is more likely to drop when using the big-big combo.
    mtbtires.com
    The trouble with common sense is it is no longer common

  5. #5
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    Quote Originally Posted by shiggy View Post
    The poor chainline is still a factor and the chain is more likely to drop when using the big-big combo.
    Never had a chaindrop off the big big combo.....and yes I ride it frequently enough....to make it through steep gullies...

    This combo should work fine on most bikes....mine is 44/22 and 34/11....

    Yes it increases wear nevertheless this is often avaluable riding combo.


    The chain is held tight because the RD is fully stretched in this gear.

  6. #6
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    I ended up stealing the 39 off my wife's bike. Everything works fine now. The teeth on my old ring are just fried.

    Sent from my Xoom using Tapatalk 2

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