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Thread: 105 FD Moving

  1. #1
    Senior Member exRunner's Avatar
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    105 FD Moving

    Of course it is moving, but what I what to know is why the physical position is changing.

    I have a 2009 Allez Compact Double with 105 and the FD has twice more out toward the big ring while riding to the point where it will not shift to the small ring.

    Today on a Century at mile 88 (I was tired and moving slower than normal) I tried to shift to the 34 ring. The brifter worked correctly, but after the second "pop" that normally shifts the FD there was a loud bang from the FD and nothing happened. The crank stopped moving for a second, but since I as soft pedaling that didn't do much, and then the cranked turned normally and I had DR rub, but was still on the 50. Trimming took care of the rub. When I got back to the barn I check the FD. It moves its normal stroke, only it is out away from the bike about half the width of the cage more than it should be. If I try to shift down the cage rubs the outside of the chain, if I try to shift back the cage rubs the inside of the chain. But the chain stays on the 50.

    I looks like the FD has physically moved out, but I don't see how that could happen. I checked if it could be pushed back in and it is solidly attached to the seat tube. It does not look bent.

    This is the second time it has happened on this bike, but the first time it was under load, so I assumed that I had goofed. This time there is no question that I shifted correctly. The bike is still under warranty, so it is going back tomorrow.

    My question is what is going on with this bike? My Tarmac has never done this. I have always thought that 105 was just a little heavier and a little less smooth, but just as reliable. The last time the shop fixed it they said it "just needed adjusting." I know how to adjust the FD so it will work, but why would an FD get that far out of adjustment in one normal shift? Has anyone seen this before?

    Thanks in advance.

  2. #2
    Great State of Varmint Panthers007's Avatar
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    As a day doesn't go buy without someone needing help with their FD, I put this in my files. I only had to post it on one thread yesterday! Anyone care to wager how many times it will be today?

    -----------------------------------------------------------------------------------------------
    Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

    http://www.parktool.com/repair/readhowto.asp?id=75

    And BicycleTutor:

    http://bicycletutor.com/adjust-front-derailer/

    When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

    It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.
    How do you keep an idiot in suspense?

  3. #3
    Senior Member exRunner's Avatar
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    Quote Originally Posted by Panthers007 View Post
    As a day doesn't go buy without someone needing help with their FD, I put this in my files.
    Thanks, but I saw that post yesterday, and already know most of it. My actual question may have been buried a little deep in a long winded post. My bad

    Quote Originally Posted by exRunner View Post
    I know how to adjust the FD so it will work, but why would an FD get that far out of adjustment in one normal shift? Has anyone seen this before?
    That's the real question.

  4. #4
    Great State of Varmint Panthers007's Avatar
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    I'd clean it thoroughly and lubricate all the moving parts. I'd suggest TriFlow or Finish Line with Teflon. The adjust it by tuning the set-screws so it can get all the chainrings properly with out any chance of over-shifting and throwing the chain off.

    My guess - and it is - why this has started happening was it wasn't adjusted correctly before. Maybe it was stuck somewhere - giving the impression it was adjusted right. Then it loosened up and is doing what you see now.

    Don't forget about the cable. In it's relaxed position on the small chainring, the cable should be taut - but not tight. And the pinch-bolt should be set at 48 - 60 inch-pounds. I go for 60ip myself.
    How do you keep an idiot in suspense?

  5. #5
    Senior Member exRunner's Avatar
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    This morning, while at work, we took my bike apart and attempted to adjust the FD. By we, I mean 3 Mechicanical Engineers with advanced degrees (probably not the best group to work on a bike, but we can read and follow directions pretty well). We took it completely apart and started over. Nothing we did could get it to work. We even followed the Shimano Tech Notes, which are more or less the same as the Park Tool notes. It would not adjust. So we put it back together and I took it to the LBS during lunch.

    They could not get it to adjust either. After 15 minutes of adjusting and cusing, someone noticed that the cage was damaged. Looking closer it was bent in 2 different directions and spread too far apart. After it was bent into position the FD adjusted correctly.

    Their guess is that I picked up road debris just as I was shifting and did not notice it. That is possible because there was a lot debris on the roads yesterday from Saturday's storms. I guess that the first time it happened it was just an adjustment issue.

    Thanks for the help, anyway.

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