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  1. #1
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    chain rub with XX front derailleur

    Anyone else experience any chain rub when the suspension compresses with their XX front derailleur? It rubs just enough to drive me crazy, only in 39 front and 36 rear. I was thinking maybe the 42 tooth derailleur would work. If it was a seat tube mount I could just slide it up a little. Believe me I tried every possible tuning trick on it and even shimmed it out a little to angle the cage. Which helped a little but it's not gone. Iwas also wondering if a XTR double front derailleur might work.
    RIDE ON,
    Scotto

  2. #2
    Are you talkin to me?
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    XX Chain Rub

    Scotto,
    I think the problem is having 10sp on your cassette. The spacing on your cassette is wide and therefor your chain is angled and rubbing on the front derailleur.
    I think that you just need to adjust the front derailleur so that it doesn't rub as much and still shifts good.
    FYI :Shimano 10sp does the same thing.
    A weekend WASTED is not always a wasted weekend.

  3. #3
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    Scotto,

    What bike are you running XX on?

    If you are using XX on a Mach 5, a Mach 429 or a Mach 5.7 then you should be using the XX FD Adapter. If you are not using this adapter, the cable will hit the rear triangle's cross section and it will pull on the cable - it will eventually break the cable, break the FD or your shifter by pulling on the cable. This could be what's happening, and when your bike compresses in it's travel, the cable is pulling the FD over so the tire rubs.

    You can Try an XTR double - we are testing it now, so it could work.
    "The face of a child can say it all, especially the mouth part of the face".
    Jack Handy

  4. #4
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    I got the adapter and that thing is a piece of art. When the suspension is compressed almost 3/4's of the way the chain is actually rubbing on the TOP of the derailleur. I put about 50 psi in the shock, ride and it rubs, shift down one cog and it rubs a little less. I shimmed it with one little washer and it's a little better, two washers it rubs in the lower cogs.
    I am trying a bigger X-0 front derailleur (higher for the bigger rings 42) and see if that works. I tried my old SLX, but that is for a triple and when in the middle of the cog, it throws the chain off the big ring on the crank. I was thinking the XTR double front derailleur would probably work the best since it's designed for their 38-42 tooth dual rings cranks and suspension frames.
    RIDE ON,
    Scotto

  5. #5
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    The X0 and X9 FD will not work - they made the body of those FD's too wide, and the adapter will not connect. I wouldn't try that.

    I'm not sure how much rub you are talking about - there is a specific FD for every chain ring option. So, if you do not have the correct FD for the chain rings you are using, then this could be the cause of the rubbing.

    With these narrower cage FD's and wide range cassettes, you may always find some rubbing in one extreme or the other. On our test bikes here with XX we can nail this down, without any shims or washers. But, it can rub in the large or slightly in the small. But not to that annoying, why the hell isn't this working correctly type rub... Just the slightly less annoying rubbing.

    I hope that helps.
    "The face of a child can say it all, especially the mouth part of the face".
    Jack Handy

  6. #6
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    Just a wild guess, but is this the Dan from Pivot? I'm the Scott with the headset thing going on.
    Back to the subject, I have no horizontal rub what so ever, it's all vertical. Even in the cross gears. I have the 39/26 cranks and I'm getting the rub with the 39/26 front derailleur. When the suspension compresses (about halfway) the chainline moves up hitting the inside of the top of the derailleur. So I figure that if I used a XX front for the next size chainring (42), this under part would be a touch higher above the chainline. I'm thinking the XTR double ring is going to be the ticket though.
    And yeah, it's one of those noises I could live with, but I'm pretty particular about my builds and I try to get everything working the best I possibly can. It just gets annoying when you're hammering thru a section and it sounds like a chainsaw scuffed your rig. It took a bit for me to figure out where and why it was doing this.
    RIDE ON,
    Scotto

  7. #7
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    Yes, I'm that Daniel.
    Nice to type and talk to you today...

    We try to set up our FD with the mindset that the bike will be in 30% of it's travel. This will pull the chain up and away from the lower part of the cage and above the FD cage ramps. If you adjust it so it is just rubbing on the inside of the cage, then it should stop rubbing when your are compressed at sag. Should is one of those words I hate - but the reality is, even we have a little bit of rub.
    "The face of a child can say it all, especially the mouth part of the face".
    Jack Handy

  8. #8
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    I waiting for the new Race Face Next SL 2x10 crank to come out. The smaller (38) chainring combined with the XTR double will be the bling bling, for both front shifting and dropping weight. Can I get a job at Pivot as a product test rider?
    RIDE ON,
    Scotto

  9. #9
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    Problem solved: I've got some miles with the new XTR double ring front derailleur. Lighter and nice action, no chain rub in any gear combo even with the suspension sagged.
    RIDE ON,
    Scotto

  10. #10
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    Quote Originally Posted by dan23
    Yes, I'm that Daniel.
    Nice to type and talk to you today...

    We try to set up our FD with the mindset that the bike will be in 30% of it's travel. This will pull the chain up and away from the lower part of the cage and above the FD cage ramps. If you adjust it so it is just rubbing on the inside of the cage, then it should stop rubbing when your are compressed at sag. Should is one of those words I hate - but the reality is, even we have a little bit of rub.
    It sounds like you've helped out scotto (or the XTR/RF Cranks did) either way it is nice to have a voice from Pivot out there to help trouble shoot. This said it still sounds like you guys are on two different planets... Scotto's issue is not a side to side adjustment so the cage ramps, stop screws or cable tension don't play a part. His issue seemed to be a vertical "chainline" which is not very easy to address on a direct mount design.
    I Just wish I could ride more!


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