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  1. #1
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    SB-66 front derailleur rubbing on frame

    Just noticed this on my frame the other day, here's an album:
    sb-66 - Imgur

    Whenever Im in the lowest gear up front and the suspension cycles, it rubs against the bolt head. I am not sure how to remedy the situation. I've tried setting the limit screws and readjusting the derailleur, but neither of those helped at all. Currently running a 3x10 with a Sram X7.

    Just wondering if anyone else has run into this problem.

  2. #2
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    I have something similar, when my suspension compresses my chain rubs on the bolt that holds the cable on my front mech. Is that what you mean ? I run a 2 x 10 with a XT front mech. Would love a solution to this as is really annoying !

  3. #3
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    Quote Originally Posted by Welchy View Post
    I have something similar, when my suspension compresses my chain rubs on the bolt that holds the cable on my front mech. Is that what you mean ? I run a 2 x 10 with a XT front mech. Would love a solution to this as is really annoying !
    On my bike, the cage for the front derailleur is actually rubbing a bolt head on the frame itself. I have not had the chain rub anything.

  4. #4
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    Oh right, different to mine then ! Maybe someone will be along to help out with both our queries !

  5. #5
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    When i built mine mounting the Direct Mount front derail as per
    the mounting guide height meant the derail body hit the bolt on the inner ring... like yours.
    So i had to increase the height of the front derail to prevent this as it was obvious
    that adjusting the inner limit screw to the minimum to allow the inner ring shift
    was not enough.. it came into contact with the bolt before this point.. therefore the only option was
    to adjust it upwards just enough until it didnt contact the bolt so it sits slightly above the bolt.... not in it

    It was an XTR front Direct Mount derail and it shifts fine. I have a spare
    XT DM derail and tried that and it was the same.

  6. #6
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    Having the same issue after replacing cables last week. Took a few laps in the bike park and heard some metal grinding noise while riding uphill on the small chainring. Looked for cracks on the frame and turned out to be the fd cage notching my lower bolt.

  7. #7
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    Had a similar problem when building my SB66c except it was going to rub the carbon chain stay not the axle bolt. Luckly I am running Race Face cranks that you can change the chain line on with spacers , so I just increased it by 1mm and set the derailuer stop screw so there was clearance between it and the chainstay through the full suspension cycle.

  8. #8
    Just Ride!!!!!
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    I dremeled my front der cage a bit where bolt hits so it clears when the rear suspension cycles and I've had no problems since then. Moving the front der higher can affect how low of a gear combo you can go when on the smallest chainring so that's why I went the dremel route.

  9. #9
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    I also have problems with my chain rubbing the inside face of the der. when the suspension compresses most of the way. If I'm not pedaling when this happens then you don't hear anything but if I'm pedaling then you hear a few links run across the metal. Haven't figured out what to do about it yet b/c I have made all the adjustments I can make and it still does it.

  10. #10
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    Quote Originally Posted by mblittle View Post
    I also have problems with my chain rubbing the inside face of the der. when the suspension compresses most of the way.
    The derailleur cages tend to change profile a bit over their height - narrowing or widening inside, to better match the rings they're intended to be with, which is probably why yours change behavior.

    Only things I can think of

    - tweak the cable tension, lessen it a bit if rubbing 'inside', tighten if rubbing 'outside'
    - pay attention to which gear on the back you're in when it happens, maybe there is a better ring/cog combination for you
    - maybe the crankset needs a little fine tuning to the chain-line, if possible, in or out. Depends on crankset I guess.

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