• 02-04-2013
    mcgong
    Chain Dropping off on 1x10
    Thought I would post this here in the drivetrain forum also to get some ideas and hopefully a solution. Maybe someone here has had the same experience.

    My components are:
    XTR Shadow+, I9 Hub, XT Cassette (11-36), RaceFace 34T Single, SRAM chain, XCX Direct Mount Chain Guide. Bike is Ibis SLR.

    Situation:
    Almost every ride, I have to get off my bike, loosen my front guide and put my chain on. I can pick up the rear of my bike about a foot off the ground, drop it, and the chain will come off the front. It doesn't matter what cog I am in on the rear. I have shorten and measured the chain to the correct length, had it doubled checked at my LBS. I have tightened the rear clutch a little. The guys at my LBS are running a similar setup and don't experience the same issue with their drivetrain(they have Giants and Yeti). They can drop their bikes from 5 ft and the chain will stay on. We spent an hour today testing various stuff and couldn't find a reason why my setup does this.
    I really don't like the C-Guides and would only run one at the very last resort if need be.

    Has anyone else experienced this sort of issue or know why my setup is so sensitive. I've included a video. Sorry my feet are in the way, but you can see what is happening. The first drop the chain is on the 11t and the 2nd drop I put it in the middle cog. The chain is coming off the bottom of the ring and then to the top is pulling the cranks in reverse.

    http://youtu.be/SUOeg6wqWW4
  • 02-04-2013
    Ben_Im
    Have you tried shortening the chain?
  • 02-04-2013
    dynamicz
    If I run a 1x anything I would recommend a short cage rear derailleur. Ever since I switch, never had a dropped chain.
  • 02-05-2013
    mcgong
    Yeah, I've tried shortening the chain. The chain is as short as it can go to accommodate the Chain stay growth too.

    Unfortunately XTR doesn't have a short cage. I was also told from Ibis that the guys there moved up to a Long cage and it solved their issue, which contradicts all that I have read. But they said it worked. I don't think it is the cage length as there is tension on the chain in every gear.
  • 02-05-2013
    dynamicz
    Then this might actually be the same issue my friend had on his xt shadow plus. Either the clutch internal spring was bad from the factory or it snapped prematurely. Shimano took care of him and sent him a replacement within a week.

    He's riding another 'type' now and very happy with it.
  • 02-05-2013
    mcgong
    Quote:

    Originally Posted by dynamicz View Post
    Then this might actually be the same issue my friend had on his xt shadow plus. Either the clutch internal spring was bad from the factory or it snapped prematurely. Shimano took care of him and sent him a replacement within a week.

    He's riding another 'type' now and very happy with it.


    I will contact Shimano as well to see what they say. Thanks
  • 02-05-2013
    mcgong
    Quote:

    Originally Posted by mcgong View Post
    I will contact Shimano as well to see what they say. Thanks

    Thinking more about this...there is plenty of tension in the clutch. There is a little play when tugging on the chain, but it more from the RD bending and giving in other places beside the clutch slipping.
  • 02-05-2013
    scrublover
    Yeah, see what Shimano says - almost looks as if the clutch isn't really doing much there at all. Meantime...

    Pick up a Zee short cage - yeah, you'll pick up some weight, but it ought to help quite a bit - shorter cage + (hopefully) functional clutch. Then, if Shimano throws you a new XTR you'll still have the Zee around as a spare.

    Make sure your XCX is as low down on the chain/ring as you can get it without a bunch of rubbing - sounds as if you've already done that though.

    It also appears to be dropping to the outside - you could add a bash guard. You'd have to then cut down the outer XCX plastic guide bits to play well with the bash, but it's easy to do, works very well, and is the cheap part of the guide - simple to grab a replacement for not running a bash.

    You get the idea here.
    http://i44.photobucket.com/albums/f1...s/IMG_0120.jpg

    The cut down XCX bit sits just inside and above the chain, the bash sits outside, and with the clutch rear I'm running, it's quiet and stays on very nicely, even with a small 30t ring not even meant for a "single ring" setup.
  • 02-05-2013
    Slash5
    Sure looks like the clutch isn't working. Haven't used one myself but from the reports on the Internet, they are stiff enough that you can feel the difference in the shifting.
    Can't the LBS try another derailleur without actually buying one?
  • 02-05-2013
    irv_usc
    I would guess that you're right about the clutch not being the problem. From the video you posted it doesn't look like the cage moved at all.

    I personally prefer the bottom push-up style chain guide vs the top mount you have.

    How is your chain line? Is the bottom bracket faced?
  • 02-05-2013
    mcgong
    Scuba, thanks for the pic. I might think about trying the zee short. I wish the XTR came in short instead of Long and Super Long.

    Slash, I've checked the clutch and it's working. I've even tightened it down more. I don't think my LBS has any extra clutch derailleurs lying around.

    Hey Irv. Chainline is good, doesn't matter what cog I'm in, it drops. I have a pressfit BB so not many options for lower guide. Pivot makes an ISCG05 adaptor but it doesn't look like it will fit on my frame.

    I tried another Chainring up front and it still did the same thing. I'm thinking it has something to do with my Hub and maybe it being too smooth.

    I made a mock up C-guide and that solved the issue...as expected. I may just have to bite the bullet and use one of those and call it a day.
  • 02-06-2013
    irv_usc
    Re: Chain Dropping off on 1x10
    I have a c-guide and love it so far.

    All the clutch does is prevent the arm from swinging forward too easily. the chain still whips around on bumps which in your case is causing it to bump off.

    Random question but is there side to side play in your rear triangle?
  • 02-06-2013
    mcgong
    no side play in my rear triangle. It's pretty stiff. I'm going to head down to FB and maybe pick