105 shifter issue

apc1
apc1 Posts: 49
in Workshop
HI

The shifter for my front mech occasionally locks up when I want to move from the small ring to the large ring and won't allow me to move gear. After a bit of playing with the inner trigger it seems to then free itself and work again normally.

It seems to happen say once every c20 shifts.

Any ideas? Frustrating because the shiofter works perfectly most of the time

Comments

  • ugo.santalucia
    ugo.santalucia Posts: 28,325
    In this order

    1) Check the tension of the cable, it should be low when on the small ring, but it shouldn't be without any tension at all... equally, when in the big ring, it should feel very tense.
    2) Replace the cable, it might be frayed, or it might stick somewhere... it's an inexpensive fix and always worth doing
    left the forum March 2023
  • Darius_Jedburgh
    Darius_Jedburgh Posts: 675
    It could be wear on the rings. I've had it happen to me, but change cables first.
  • pilot_pete
    pilot_pete Posts: 2,120
    Darius_Jedburgh said:

    It could be wear on the rings. I've had it happen to me, but change cables first.

    How does wear on the rings lock a front mech up?

    I’d say it’s cable inner/ outer or a problem in the shifter itself.

    PP

  • Darius_Jedburgh
    Darius_Jedburgh Posts: 675
    Don't know why, but I have had problems changing when rings are worn. Had it once on my TT bike. Got less than 50 yards on a float day because the chain jammed changing into the big ring after starting in the little ring. Wasn't a happy bunny. New rings sorted the problem. Didn't get my float day back!!!
  • thecycleclinic
    thecycleclinic Posts: 395
    Shimano shifter fray cables.
    www.thecycleclinic.co.uk
  • pilot_pete
    pilot_pete Posts: 2,120
    Darius_Jedburgh said:

    Don't know why, but I have had problems changing when rings are worn. Had it once on my TT bike. Got less than 50 yards on a float day because the chain jammed changing into the big ring after starting in the little ring. Wasn't a happy bunny. New rings sorted the problem. Didn't get my float day back!!!

    Hmmn, fair enough, but your was a jammed chain against the rings/ mech, whereas the OP says the shifter jams, not the chain.

    PP

  • thebigman
    thebigman Posts: 58
    Not sure what series but 5700 was prone to fraying cables all the time. I would put my money on a cable issue..

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