Front mech won't shift.

Frank the tank
Frank the tank Posts: 6,553
edited June 2010 in Workshop
Was out on a ride today and my front mech decided it wasn't going to shift from the big ring into the small one. It's a 105 I think the problem is within the mechanism within the lever.

Any thoughts on this anyone.

Thanks.
Tail end Charlie

The above post may contain traces of sarcasm or/and bullsh*t.

Comments

  • random man
    random man Posts: 1,518
    Mate of mine had this problem - he lent his bike to a friend who was a bit heavy handed :wink:
  • Frank the tank
    Frank the tank Posts: 6,553
    I see it's your first post, welcome aboard mate. Your mate ought to be careful who he lends his gear to. :roll:
    Tail end Charlie

    The above post may contain traces of sarcasm or/and bullsh*t.
  • plowmar
    plowmar Posts: 1,032
    What makes you think that it is the mechanism in the lever?

    I had the same problem in my MTB triple, with it just not changing out of the large ring. All I had to do was give it its first wash in 7 years, but I am sure that will not be your problem.

    The other option I was given was to strip down the dérailleur and rebuild it, which I guess is the same as giving it a very good wash.
  • Frank the tank
    Frank the tank Posts: 6,553
    It happened totally out of the blue, like all my bikes it's been well maintained but although the lever moves inboard the mech resolutely refuses to shift.
    Tail end Charlie

    The above post may contain traces of sarcasm or/and bullsh*t.
  • Simon G
    Simon G Posts: 41
    Frank the tank
    It might be worth trying to establish whether you have a lever problem, a cable problem or a mech problem as a starting point.

    1. If you're happy enough with undoing the cable at the front mech, you could check whether the mech returns 'home' (i.e. check that it is naturally returning to the lower ring position once free of the influence of the cable.

    2. Whilst the cable is free, you could try and see if the inner moves smoothly inside the outer.

    3. If the cable is nice and free, just see if the fromt mech clicks healthily under it's own steam (i.e. without the influence of the cable or front mech). Try shifting it up and down to get a feel whether it is working or not

    If you're un-nerved by the idea of undoing the cable, you could try and shift the front mech onto the lower ring using your STI / lever and then see if that has actually loosened the cable (see if you can grab a handfull of cable where it is exposed under the top tube)

    I'm going to put money on the problem being a gunked up cable (i.e. perfectly healthy cable and front mech which is being inhibited by a stuck cable. Have things been feeling a bit tight on the upshift to the big ring lately?
    Simon G
  • Frank the tank
    Frank the tank Posts: 6,553
    Thanks for the advice. The bike usually sits on my turbo and I lent it to a mate for him to have a go on, so he could get a feel how a better bike rode.

    I've had a word with my LBS and he told me the shifter is for both double and tripple c/ring set ups and if you're not careful it's possible for rhe shifter mechanism to break. He said to bring it in and would get me a replacement under warranty.
    Tail end Charlie

    The above post may contain traces of sarcasm or/and bullsh*t.
  • Buckled_Rims
    Buckled_Rims Posts: 1,648
    The 105 Left hand shifter has a history of faults. My 105 has a horrible clicky/stuck motion on it. I find I can only really shift if the gears on the back are near the middle of the cassette.

    As you say, the LH shifter is a double/triple one. I think there's a plastic tab inside that can break (best to google 105 left hand shifter for more examples) that can't be fixed and needs a whole trigger replacement! I'm dreading mine breaking.
    CAAD9
    Kona Jake the Snake
    Merlin Malt 4
  • cooper.michael1
    cooper.michael1 Posts: 1,787
    Yeah another post today is regarding 105 left shifter problems. If you search on the forum or google, you'll see there are many many complaints of broken levers.

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