Front Mech potential replacement

j.higson
j.higson Posts: 28
edited January 2013 in MTB workshop & tech
hey there guys,

im trying to get my bike ready for a regular 20 mile a day shift to uni and back and am having a lot of trouble with the front mech. no matter what i do i cannot get it to shift smoothly from first to second and it definatly won't move from second into third. i have tried everything i could do, putting lots of tension into the cable, putting a less tension into the cable, altering the high screws, the height.

the high screw doesnt alter anything at all on the mech. it isnt that old but could it be time to completely replace the thing? been working on it all day and im about to rip all my hair out.


any advice would be epic.
thanks
Specialized Allez 2013 Compact

Often found on the roads of the North West.....

Comments

  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Has it worked correctly?
  • j.higson
    j.higson Posts: 28
    sorry, forgot to mention, my current mech is a Shimano FD-M190.
    Specialized Allez 2013 Compact

    Often found on the roads of the North West.....
  • j.higson
    j.higson Posts: 28
    Chunkers1980 wrote:
    Has it worked correctly?

    no its always been a bit crap and always struggled between gears, its just gone a lot worse
    Specialized Allez 2013 Compact

    Often found on the roads of the North West.....
  • marz
    marz Posts: 130
    The chain just sits there, refusing to jump down a gear even though it's rubbing against the mech?

    If so, it's not so much cable tension as cable length. Is this a road bike or mountain bike?

    Do you have anything like the picture below along the run of the cable? Maybe at the shifter, maybe at eh mech?

    parlee_z5_cable_adjuster_600.jpg

    You may need to adjust cable length by giving an adjuster like the picture a small turn (make all adjustments in quarter turns and test). In your case maybe half a turn clockwise.

    If there's no adjuster, then maybe just release the cable through the mech a mm or so. Easiest done when the mech is in its lowest position. When in lowest position, loose cable, turn lower limiter a half turn, retighten cable and test.
  • j.higson
    j.higson Posts: 28
    i will take some pictures in the morning when it isnt dark to show you my problem.

    the chain will not move at all from second to third, ive always had to keep my thumb on the shifter pushing it hard to achieve third when riding previously. ill give it a try when its in its lowest to add more tension as there isnt an adjuster as youve shown except on the actual shifters on the bars.

    when i manually put the chain onto the third cog it is rubbing against the inside edge of the mech (inside edge of the outside part), moves perfectly fine from 3rd to 2nd to 1st but no amount of adjustment to the high limiter is moving it from this position. The screw literally does nothing but as every tutorial on the internet is saying to use these screws to get the chain to sit in the middle of the mech then i cant do anything really.
    Specialized Allez 2013 Compact

    Often found on the roads of the North West.....
  • j.higson
    j.higson Posts: 28
    also it is a hard tail mountain bike
    Specialized Allez 2013 Compact

    Often found on the roads of the North West.....
  • marz
    marz Posts: 130
    It's not the tension, but the length of cable from shifter to mech and the adjuster on the shifter is the key. Give the adjuster a turn or so anti-clockwise when the chain is in 1st. The mech should move slightly away from the chain ring. Test to see if the chain shifts correctly, if not try another turn anti-clockwise.

    The limiter screws have very little to do with positioning the chain over the chain rings, they are just there to stop the chain going off the top and bottom chain rings.

    These seems to be a good video guide...

    https://www.youtube.com/watch?v=dAP4aHv2dy0

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