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  1. #1
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    Reputation: Bethany1's Avatar
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    Front Derailleur Fix?

    Front derailleur is hosed for sure after I got it up the stand. The chain gets caught between the middle ring and the derailleur while going up or down. Not sure if the pieces are bent inwards catching the chain as it goes down or if the limit screws need adjusting.

    If I need a new front derailleur what do you all suggest? They make different ones for what you are doing.
    Attached Thumbnails Attached Thumbnails Front Derailleur Fix?-img_2398.jpg  


  2. #2
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    Chances are that the cage is just bent or twisted. The inner and outer plates should be more or less parallel to each other and to the chain. Don't be afraid to bend it as needed or loosen the clamp if the whole derailleur is twisted. When shifted all the way to the outer ring, the bottom edge of the cage should be around 2-3mm above the chainring teeth. The clearance is adjusted by loosening the clamp and moving the derailleur up or down.

  3. #3
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    I'm wondering if I bent the chain rings. You can see the rings move when you look through the derailleur. It's a FSA ISIS Alpha drive 44/32. When I checked the limit screws, you can hear the chain rub against the derailleur, then not rub, rub and not rub.

    I'll take it to the LBS after Christmas and see what's going on. Derailleur is a Shimano SLX not a SRAM X7 like Salsa has in it's parts list.

  4. #4
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    Loose bottom bracket can cause the rub/no rub thing, too. Can you rock the crank arms from side to side? Bent rings or individual teeth are possible. They can usually be bent back ito place with pliers. Don't be afraid to mess with your front derailleur - it's a dumb, primitive thing (and fairly cheap, too).

  5. #5
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    No rocking back and forth with the crank arms. No creaking or any noise. Talked to my LBS today. I'm taking her in on Thursday.

  6. #6
    Icebiker
    Reputation: Bugeye's Avatar
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    For straightening chainring teeth, suggest you use an adjustable wrench. Keep the chainrings on the crank, and be sure to wedge something (like the middle (e.g. handle) of a box wrench between the chainring in question and the bashguard (or next chainring) to keep the chainring itself from warping as you apply pressure to the tooth/teeth.

    Can't tell from the pic what's wrong with the FD...but is it possible that it's slipped down the seat tube and not providing enough clearance for the middle ring?

    Good luck!

  7. #7
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    No rocking back and forth with the crank arms. No creaking or any noise.
    The BB would have to be terribly loose if you were able to see it. They're loose if you can feel any movement at all. Even if the end of the crank arm moves less than a mm. Just enough to feel, and maybe hear a slight click, or hear nothing at all. I'm not saying that your BB is or isn't loose, just that it doesn't take much.

    Ask someone to show you what a loose bearing feels like, sometime. It doesn't have to be a crank and BB; it could be a wheel. But once someone shows you what it feels like, then you'll know what to look for.

    It sucks that your bike is offline for the better part of the week. I hope that you have another bike to ride if you get the time over Christmas.

  8. #8
    Nemophilist
    Reputation: TrailMaker's Avatar
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    Hey;

    Drop the chain and use the derailleur cage as a gauge. Spin the cranks, watch for any wobble, and decide which way it is out of true. If you find a broad shallow deviation, just grab it with your fingers and give it a tug, or bump it lightly with the dowel, screw driver, hammer handle, or whatever is handy. If it is more localized or of greater deviation, using the crescent wrench technique previously described works best. Vice grips will work too if that's all you have.

    I had a buddy fold his Granny in half on a ride once. Not sure how he managed that, but using my tool kit and a couple of rocks as hammer & anvil, I straightened it out so well that he never bothered to replace it!

    If you find no significant deviation, look toward the derailleur itself for clues. Like Smoove said, they are a pretty blunt instrument, so don't be afraid of tweaking it around to get it to work. Whatever you need to do is fine. Working is working, and if they do, what's the question?
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  9. #9
    DIY all the way
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    This is either bent chainrings, loose cranks, loose chainring bolts, or a bent spider.

    If it was the derailleur, it would touch all the way around the pedal stroke.

    Magura

  10. #10
    mtbr member
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    Trail,

    One of the first things I did was take the chain off to check the rings. Looks like it was wobbling. What's the quality of the stock 2012 Mukluk BB?

    No tools in my garage except for what I've picked up for basics. I don't have light in my garage unless the garage door is open as well. Today's high is 25 degrees so I'm not about to mess with the bike today. Hubby won't let me bring the bike and stand into the kitchen either. LOL. Snow is pretty much gone since the high on Saturday was 48.

    I still have my Fargo so it's all good. I've thought about putting a road tire on the back for my winter trainer and using it for the cold days. It's Christmas week so nothing is open until Wednesday anyway.

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