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  1. #1
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    New question here. 2x9 from a 3x9 = chain falling due to ramps?

    i run a 2x9 which was originally a 3x9 XT setup.
    with a bashguard...no problems.

    Now, I'm trying the mrp 2x guide / bash combo and the chain falls of the "big" ring when shifting.

    My LBS says it has to do with my 32t ring that I bought. It's ramped and pinned.

    they told me when shifting, the chain is getting caught on the ramps and trying to shift into the 3rd ring that is no longer there. Now that I think about it...it makes sense to me. The old set up worked because the bashguard lip kept the chain on.

    Note: everything is brand new, and the LBS set the front derailer up properly...so it isnt a question of adjustment.


    Do I need to get a new ring that has zero ramps and pins to solve this problem?
    I need a 32t ring...any suggestions???

    thanks in advance

  2. #2
    human dehumidifier
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    The ramps that would move the chain to the 3rd ring are on the 3rd ring - and that ring isn't there.

    The same LBS that told you the ramps were the problem set up the front derailleur? I'd question that it's done right. You know it's not rocket surgery to set the limits, right? Give it a look for yourself.

    I ran a 2x with stock LX rings and a bash guard for several seasons with no chain drop problems. All I did was replace the big ring with the bash and limit the derailleur.
    I Just Wasn't Made For These Times

  3. #3
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    yes i understand....like i said...i ran a bashguard with zero problems.
    the mrp 2x is not a bashguard that bolts in place of the 3rd ring.
    It attaches to the iscg05 tabs and uses a "taco" bash.

    they played with the limit screw...they said it's not the problem.

    would the ramps cause the chain to migrate off the 32t ring in search of the phantom
    3rd ring?

  4. #4
    human dehumidifier
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    I don't see how the ramps on the chain ring could cause it to ghost shift upward. The ramps would be under the chain and are intended to pull the chain up to the ring that has the ramps. Plus, it didn't do it before, if it was trying to throw the chain with the bash guard on it, it seems you would've noticed noise or something even if the chain never made it all the way off the ring.

    Is there any adjustment on that taco guide? Seems like if that's not on the ring it could walk the chain one way or the other, but I have no experience with those.

    BTW, look at the bikeradar verdict on this page -> MRP 2x Chain Guide Review - BikeRadar From the last paragraph
    However, we found we still regularly lost the chain from up top.
    I Just Wasn't Made For These Times

  5. #5
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    ramps and pins don't throw the chain up, they collect it from below. your lbs is full of morons. have the FD properly adjusted by someone who is not a complete idiot, or do it yourself for that matter, shimano techdocs is great source of info. then ditch the mrp and go back to your regular bash ring, and if you still need a chainguide on top of that solution, buy a bionicon c-guide, problem solved.

  6. #6
    LCW
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    2x9 from a 3x9 = chain falling due to ramps?

    I converted my 3x9 to 2x9 and also run the MRP 2X guide. You need to adjust the front derailleur. Your H limit screw is probably not set right and allowing the chain to go to far. It's a balance. If you don't let it travel far enough the shifts into the middle (which is now the "big") ring will be poor.

    I run 22/36 front rings, no bash, and the 2X guide no issues. Smooth shifting. No dropping chain off the big ring. Required tuning as one would expect when changing anything in a drivetrain. Your LBS is not very impressive if they can't help more than that. Neither is bikeradar for that matter.
    2011 Yeti 575 - Fox Float 36 RC2 160 - 31.5 lbs

  7. #7
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    Quote Originally Posted by LCW View Post
    I converted my 3x9 to 2x9 and also run the MRP 2X guide. You need to adjust the front derailleur. Your H limit screw is probably not set right and allowing the chain to go to far. It's a balance. If you don't let it travel far enough the shifts into the middle (which is now the "big") ring will be poor.

    I run 22/36 front rings, no bash, and the 2X guide no issues. Smooth shifting. No dropping chain off the big ring. Required tuning as one would expect when changing anything in a drivetrain. Your LBS is not very impressive if they can't help more than that. Neither is bikeradar for that matter.
    i see the concensus here...so I'm fine running a 32t shimano chainring with ramps because it should not impact overshifting of the chain....AND all I need to do is play with the front derailer settings?

    I know for a fact that this was the 1st 2x guide that the shop has installed...so maybe they tried what they thought would solve the issues.

    which way should I adjust the H limit screw to avoid the chain overshifting and falling off the "now 32t big ring?"

  8. #8
    human dehumidifier
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    You need to turn the screw CW so it stops the travel sooner. I recommend you get your head down there with a light and see what those screws do then you'll understand.
    I Just Wasn't Made For These Times

  9. #9
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    thanks...that's the weird thing...the LBS said they adjusted it every possible way and it still happens. They have it where it is pretty good...but it will def happen on the trails numerous times if I try to shift from the 24t to the 32t.

  10. #10
    human dehumidifier
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    Yeah that's why I recommended you look at it and understand how it works. You don't have to rely on the LBS getting it good enough so you're back out the door and they're back on facebook or whatever. Take a screwdriver riding with you and if the chain still falls off, give the screw another 1/2 turn and try again.
    I Just Wasn't Made For These Times

  11. #11
    Ninja Master Powers
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    Quote Originally Posted by freeriderB View Post
    yes i understand....like i said...i ran a bashguard with zero problems.
    the mrp 2x is not a bashguard that bolts in place of the 3rd ring.
    It attaches to the iscg05 tabs and uses a "taco" bash.

    they played with the limit screw...they said it's not the problem.

    would the ramps cause the chain to migrate off the 32t ring in search of the phantom
    3rd ring?
    I'm taking a guess here. The issue could be the way the 2X is set up. Out of the box it is designed for true 2x (9)(10). It will work with a converted 3X crank set, but, there are some shims needed and they come withe the MRP guide.

    Put the shims in line it all properly and likely you'll be shifting fine.

    How I learned this is that I had the exact same problem when I converted my brand new XT 3X10 to 2X10 when I got my Nomad C last year. I couldn't figure out why it wouldn't work.

    Dug around on the MRP web site found the info about installation on a converted 3X10 followed it and all was well.

    I've since taken it off and put a ISCG05 Black Spire Stinger with a bash in its place. But that had nothing to do with the 2X not working, just with the plastic being eaten up by chain lube etc.

  12. #12
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    So you are running a 3x9 with the big ring removed right? And the chain is going over the middle ring because there is no big ring?

    Big ring or not, it should not be going over unless the limit is completely off.

    Sorry but the LBS didn't adjust it right. I'm assuming you are still using a 3x front shifter right?

  13. #13
    LCW
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    2x9 from a 3x9 = chain falling due to ramps?

    freeriderB - one thing that might also help is swapping the front derailleur for a 2-ring one (they are shorter)... You can find an SLX one fairly cheap. I personally found this improved the shifting on a converted 2x9 setup.
    2011 Yeti 575 - Fox Float 36 RC2 160 - 31.5 lbs

  14. #14
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    [QUOTE=forge55b;10298945]So you are running a 3x9 with the big ring removed right? And the chain is going over the middle ring because there is no big ring?

    Big ring or not, it should not be going over unless the limit is completely off.

    Sorry but the LBS didn't adjust it right. I'm assuming you are still using a 3x front shifter right?[/QUOTE

    Yes...same 3x shifter. Worked fine as 2x9 with bash

  15. #15
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    Yeah it just needs to be properly adjusted. Or the front derailleur might be messed up.

    Without any of us actually seeing it (post a video cause your LBS seems clueless) we can only make guesses really. Educated guesses at least.

    Long story short, just learn how to adjust a front derailleur yourself. It isn't nearly as difficult as people make it seem once you actually learn the mechanics of it.

  16. #16
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    on a separate note...
    my small ring is a brand new Race Face 24tooth.
    the shop said that the tops of the chain ring bolts are not flush and clearance is minimal because the ring does not have a recessed area for the bolts to sit in.

    I've had numerous Shimano 22t rings...and I can't remember any having a recessed hole.

    Can someone make a recommendation?
    I'm looking for a 24t...but will use 22t if necessary.

    Is it possible that my 2X guide just needs additional spacers to provide proper clearance?

  17. #17
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    Quote Originally Posted by syl3 View Post
    ramps and pins don't throw the chain up, they collect it from below. your lbs is full of morons. have the FD properly adjusted by someone who is not a complete idiot, or do it yourself for that matter, shimano techdocs is great source of info. then ditch the mrp and go back to your regular bash ring, and if you still need a chainguide on top of that solution, buy a bionicon c-guide, problem solved.
    DITTO
    I went from a 3x9 to 2x9 last year absolutely no chain drop .Its just a fine balance of the over travel adjustment screw.
    I ended up how ever wanting more than 36 front so snagged a blackspire dh ss 38 ring for 15 bucks. Still shifts just find with no ramps and pins using xo shifters.

  18. #18
    LCW
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    2x9 from a 3x9 = chain falling due to ramps?

    OP - you're running 24/32 rings?? That's only an 8 tooth jump... That could maybe be part of your problem.

    Standard is 10 tooth jump (22/32), and I've run 22/34 and 22/36 (my latest config) without any issues.

    With such a small jump from 24 to 32, there might not be enough room for the ramps to do their thing?
    2011 Yeti 575 - Fox Float 36 RC2 160 - 31.5 lbs

  19. #19
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    I had this same exact issue on my nomad. As others have said it could be adjustment needed, but it possible just adjusting wont fix it. You're still running a 3x specific FD, so without a bash guard the FD is sitting quite a bit above your now 'big' ring, which easily allows the chain to ju,p off to the outside. No amount of limit screw adjusting can fix that.

    If there is room on your frame / FD move the FD down the seat tube. If not, you'll need to do what I did and find a 2x9 specific FD. The only one I could find are the shimano SLX. Look on their site for the 2x9 model # as the SLX does Come in different models for 9 & 10 sp. Once I got that on my bike, problem solved. And the SLX derailluers are pretty inexpensive.

  20. #20
    LCW
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    2x9 from a 3x9 = chain falling due to ramps?

    Running a 2x10 front derailleur will work too. I'm running the 2x10 M645-E SLX front derailleur on my 575. Works perfectly even with my 9spd setup.
    2011 Yeti 575 - Fox Float 36 RC2 160 - 31.5 lbs

  21. #21
    No Clue Crew
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    Everything said here is correct. The FD does need to be moved lower if possible. If not, it wouldn't hurt to drop a few bucks on one of the smaller 2x specific FDs. Also, did they shorten your chain properly when the big ring was removed?

  22. #22
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    To set the front deraileur to be limited to the center chainring, you may need to change the screw that adjusts the "h"setting on it, so it reaches the moving plate sooner on its travel.
    You may also lower the FD, as said, but depending on the rear suspension, this will cause the chain to rub, for the nomad, I had to keep the FD on the original position when it had a 44 tooth big ring.

  23. #23
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    If I'm understanding you correctly I think the answer is a specific 2x front derailleur.
    Honestly, it's worth the investment. And will solve all your problems right away.
    I speak from experience.
    I had a triple crank that I converted to a double (24/36) with a bash. I kept the 3x front derailleur and simply used the limit screws to stop it.
    With the bash on everything worked fine. It was when I took the bash off (I didn't need it and just didn't like the look of it) that the problems started.
    No matter what I did I couldn't get it to not drop off the front AND shift well.
    After much effort I bought a dedicated 2x front derailleur (I went for an XTR but you don't need to).
    Problem solved right away. And the shifting is incredible.

  24. #24
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    update - i took the advice of some of you and pulled a screwdriver out.
    All I did was turn the "H" screw on the FD 1/4 turn counter clockwise and it shifts perfectly fine.

    The shop had the chain drop when it was in the stand.
    When I tried to shift from the small ring to the big on the trail, it wouldn't quite get there.
    So the problem on the trail was just the opposite of a chain drop...so i went counter clock wise.

    thanks for all the input and advice. I'll trail test the shifting this weekend.

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