Front gear problem

Super Saint
Super Saint Posts: 22
edited August 2008 in Workshop
I am trying to adjust the front gear, with not a lot of success.

I can get one chain ring set up, but when I try to do the other it all goes wrong.

I am currently stuck on the big chain ring, and am unable to shift down.

What order do I need to do things.

When the chain is on the smallesr ring, should the cable be slack, if so how slack, very or just a little.

I have a Giant SCR 4.0.

When setting the limit screws, do I need to allow for trimming, or do I still leave a small gap.

I've had it to my LBS but when I tried to change up to the big chainring it only just managed to push across, and wouldn't move at all on the second attempt.

Any help greatly appreciated.

(The initial problem was the chain was rubbing in 6,7,8 at the back)

Comments

  • topdude
    topdude Posts: 1,557
    Sounds like you have a double chainset.
    Loosen the cable clamp on the front mech, the mech will move inwards and rest on the inner limit stop.
    With the chain on the small front ring and big rear sprocket adjust the inner limit screw so there is a small gap (approx 1mm) between the inside of the cage and the inner edge of the chain.
    Re-connect the cable to the clamp so the cable is just under tension (not loose and not tight).
    Now while turning the cranks change up to the large front ring and down to the small rear sprocket.
    Adjust the outer limit screw so there is a 1mm gap between the inside of the cage and the outer edge of the chain.
    Try changing the front mech down and up using all the rear sprockets.
    This is a starting point, you may need to adjust the cable tension a little to allow the front mech to reach both limit screws.
    Bear in mind it is not always possible to use the big front / big rear and small front /small rear combinations as the chain is running at too much of an angle.
    He is not the messiah, he is a very naughty boy !!
  • Ambermile
    Ambermile Posts: 117
    I had this issue with an XT and a triple set... turned out I had fitted the mech at slight angle, hell of a noisy ride on the smaller back gears :shock:

    Arthur
    The Beastie


    Sic itur ad astra
  • Super Saint
    Super Saint Posts: 22
    Totally hacked off with this now, I was nearly there, but not quite, now it's all up the wall again, well and truly had enough.

    I know I should be able to sort this, but I am getting nowhere, bikes only two weeks old.

    I am going to take it to another shop, and hope they make a better job of it.

Categories