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  1. #1
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    Why is my chain dropping???

    I recently switchted from a 26er to a 29er and moved my XT groupset over(40/28 front and 11-36 rear). I kept the Sram FD that the 29er came with because it needs a direct mount FD.

    My chain keeps droppin off the big ring on the outside. (NOT during shifting). It usually happens after I coast over a rough section and then try to pedal again. Another example is getting on top of a large rock (1 - 2 ft tall) at the base of a climb then standing to grind up the climb and have the chain drop.

    I took it to a shop who said the FD cable tension was loose. That didn't fix it. Took it to another shop who said the chain was damanged and replaced it. That didn't fix it. I decided to purchase an XT FD since I never had this issue when I had an XT FD on the 26er. That didn't fix it.

    Has anyone had this happen before? Does anyone have any possible solutions?

  2. #2
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    I'd check the chainline.

    *EDIT* ( Assuming the chainring isn't worn. )

  3. #3
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    Strange. I would think a chainline problem would cause the chain to drop to the inside, not the outside. Loose cable tension would cause it to drop off the inside as well. It is possible that the 40 tooth ring is bent, or has a bent tooth.

  4. #4
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    That is odd. Nt sure what crank and BB u have, but make sure the drive side is not spaced in - board too far.

    A too long chain may also be part of th problem.

  5. #5
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    Chain is about 3 weeks old. The crank is XT785 with Shimano Pressfit BB.

    When in the big ring the RD cage is pointing straight down or slightly forward depending on the gear in the back. In the little ring it is folded back.

    I tried riding some in the little ring only yesterday and could not get the chain to drop. I wonder if the RD cage kicks forward when I'm going over a rough section and jumps the chain off the ring. Sometimes I can ride the chain back up, but often it is totally dropped.

    I feel like I can keep it on if I concentrate on keeping some forward pressure on the pedals, but that also affects the way I ride.

  6. #6
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    Re: Why is my chain dropping???

    When on the large ring and largest cog, your RD should be way forward, almost straight. Else your chain is probably too long

  7. #7
    ballbuster
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    Easy. Check the limit screws on the front derailleur, check front derailleur orientation, check chain length.

    There is a tutorial on the Park Tool website on how to adjust your front derailleur. First off, it isn't supposed to be perfectly parallel to the centerline of the bike.

  8. #8
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    So do the Park checks and if that doesn't work and since you are buying stuff you should just get it over with with an XT Shadow Plus.
    Just for fun spin your big ring 180 degrees.

  9. #9
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    Or you could buy one of these. I had the same issue with my 3X10 when I was riding over bumpy trail sections. My chain would fall off the large chain ring to the outside. I had my FD adjusted more then a few times. Now I do not have that issue anymore.

    Mark
    Attached Thumbnails Attached Thumbnails Why is my chain dropping???-img_20130415_222234.jpg  

    2012 XXL Carve Expert

  10. #10
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    Why is my chain dropping???-img_20130425_244241_339_zps22d652c1.jpg

    Even better SRAM x9 type 2 no lever to engage like the shimano. Zero chain slap no chain drops shifts smooth

  11. #11
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    Quote Originally Posted by RacerX82 View Post
    Click image for larger version. 

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    Even better SRAM x9 type 2 no lever to engage like the shimano. Zero chain slap no chain drops shifts smooth
    Nice looking RD. What do you have to dis-engage to remove your wheel? That clutch switch is for removing the wheel. I have not seen the X9 model but it looks nice. I got a great price on the XT, SLX was not ever making it to my ride but the XTR looked very nice. $225 for the XTR did not look nice. On line my XT is about $125, so my LBS matched it and it is one of the best investments I have made yet.

    Mark
    2012 XXL Carve Expert

  12. #12
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    I had a brief problem with the chain dropping of the outside on a past bike. Reading the derailleur instructions carefully and setting it up exactly as instructed fixed it. Also making sure the chain isn't unnecessarily long will stop any sloppy bouncing around. The new generation derailleurs with the clutch will be an upgrade on each bike as they wear out.

  13. #13
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    Quote Originally Posted by millertm View Post
    Nice looking RD. What do you have to dis-engage to remove your wheel? That clutch switch is for removing the wheel. I have not seen the X9 model but it looks nice. I got a great price on the XT, SLX was not ever making it to my ride but the XTR looked very nice. $225 for the XTR did not look nice. On line my XT is about $125, so my LBS matched it and it is one of the best investments I have made yet.

    Mark
    You just push the cage towards the front of the bike and push in the lock button to remove the wheel. It works really well.

  14. #14
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    Quote Originally Posted by eb1888 View Post
    So do the Park checks and if that doesn't work and since you are buying stuff you should just get it over with with an XT Shadow Plus.
    Just for fun spin your big ring 180 degrees.
    +1 on the above

    keep dropping the chain on my Sram drivetrain until I swapped out the RD for the type 2, fixed the problem.
    Self employed picture framer, selling the odd cycle part/light as a sideline
    youtube / strava. Back on a bike after 25years

  15. #15
    The Missing
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    Make sure your rear der. is not whipped, I had my XX for 1.5 seasons, the tension felt strong enough however under harsh conditions it would drop the chain. Replaced the rear Der. and never had the problem again.

  16. #16
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    Thank you everyone for your input! Shadow Plus RD has fixed the problem.

  17. #17
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    Quote Originally Posted by pernfilman View Post
    Make sure your rear der. is not whipped, I had my XX for 1.5 seasons, the tension felt strong enough however under harsh conditions it would drop the chain. Replaced the rear Der. and never had the problem again.
    Would it falling off under heavy load like a steep hill climb do the same thing? I went 1x9 and the chain falls off to the outside under heavy load, I can blast through ruff stuff ok but when climbing is when it pops off. I put a bash guard on and will see if that stops it. Can't hurt it at least it will protect the ring from rocks and fallen trees I go over. Its on my FS, my HT is setup the same way and dosent suffer from this, I was kinda stumped when it popped off on the climb. Raceface cranks and chainrings on both bikes.
    Giant XTC 2 29er
    KHS Flagstaff 29er FS
    Neon Bow Trials Bike
    Norco Fluid 9.2 29er FS
    Norco BIGFOOT FATTY

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