Help please - Shimano 105 FD shifter

iamzou
iamzou Posts: 14
edited September 2016 in Workshop
Hi - wondering if anyone can give me any pointers here. I'm having problems with my Shimano 105 shifter (it's working with a Tiagra FD). I have 2 chainrings at the front. I can get it to shift up to the top / outside ring, but can't get it to go back down.

If I undo the cable on the FD, the shifter is pulling / tensioning the cable up and realising it with the correct 'click' when I simulate dropping down to the inside / bottom ring. I can repeat this over and over. As soon as I reconnect the cable to the FD, it will shift up, but not down, the lever won't click and just seems to move freely. It's like it's working when there's no load on the shifter, but when the load (FD) is applied, it stops doing what it should.

I've tried taking the chain off, and moving the FD up the seat post so that there's nothing in the way, just to simulate the movement, and the problem persists. I've stripped the cable, WD40'd the shifter and the FD, the cleaned the cable runs etc. The FD moves freely when I move it by hand.

Is the shifter goosed? Can anyone suggest anything else? It's bugging me that the shifter works with no load on, wondering if I'm missing something obvious?

Cheers

Comments

  • tim_wand
    tim_wand Posts: 2,552
    Check your cable routing, it sounds like its getting stuck somewhere against the outer. Also have you routed the cable the right way into the mech and under the b/b ( if it doesn't run down from the top tube/ seat tube. CX style )
  • k-dog
    k-dog Posts: 1,652
    If it's 5700 those shifters had some problems in the early days and the symptoms sound quite like that.

    It's worthwhile checking your in the right part of the levee throw - so make sure the lever is clicked all the way down before you attach the cable - click the small lever a few times. If you connect it when that's not right then you can just be using the trim and the cage won't move far enough to change ring.
    I'm left handed, if that matters.
  • CiB
    CiB Posts: 6,098
    I recall a similar thing on my 105 setup a few years ago and resolved it by running the cable to the other side of the clamp bolt on the FD. Can't remember which side was correct but there are only two options. Try that, assuming all else is ok, and report back.