Basic rear mech thing

Jterrier
Jterrier Posts: 97
edited October 2017 in Workshop
This is a simple thing that i am prb getting wrong. I am tuning the rear mech after installing new cable and outers. I have set the low and high limit, and then when i install the cable i am finding i need to add so much tension to get clean shifts that it is creating a false high limit, i.e the cable tension is artificially bending the mech inwards whilst on the smallest sprocket.

Its an old 10spd tiagra fyi. What have i missed.

Comments

  • jgsi
    jgsi Posts: 5,062
    Release the cable and start over a gain... I find a fresh cable needs a few goes for it to 'bed' in properly.
    Just make sure at shifter end it is properly seated - give it a good tug.
    When nipping up the cable at mech end, a fourth hand tool is useful but I make do with mole grips.
    http://www.chainreactioncycles.com/park ... rd|22038UK
  • Guernsey Donkey
    Guernsey Donkey Posts: 144
    Have you got the cable correctly routed at the derailleur clamp? There is a groove on one side below the bolt that the cable sits in.
  • sam_anon
    sam_anon Posts: 153
    There's a good GCN video on youtube regarding indexing rear mechs and compressing cable fixings to get great shifting.

    Never tried it mind.
  • nuclearred955
    nuclearred955 Posts: 81
    If you were just replacing the cable & no other components, it's unlikely that you would need to touch the limit screws. Go back & make 110% sure they're precisely where they should be.

    Once these are correct, Shimano recommend that cable tension is adjusted with the rear mech in the middle of the cassette - so on a 10sp, with the chain on the 5th or 6th sprocket. From memory, the correct tension will have the top jockey wheel fractionally inboard of the sprocket it's aligned with.

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