chain rubbing on front mech

scotto

On my gt avalanche the chain rubs like mad on the front mech when in the outermost ring on the crank and the smaller 3 rings on the cassette.

I have used the parker book to adjust the low screw and got that right, but even with the hi screw right out I still get the same problem, the chain does not fall off at either end..

I should add that I have just put a new chain on and cut that one link short but am going to put another chain on when it arrives, but can anyone geuss what the issue may be please or could it be the shorter chain causing the issue?

many thanks

nicklouse

sounds like not enough tension in the cable as the mech is not moving out enough.

JonnyN

Try adding tension to the cable.

scotto

thanks, is this a case of undoing the bolt and pulling the cable really tight then doing it back up again?

nicklouse

no use the adjuster.

Try reading the How tos on Parktools as it seems the info you have been reading is seriously lacking.

scotto

ok thanks will do, info was from the park book btw not parker :-
) my mistake, will read some more and give it a go.

captainfly

Ifyou can physical pull the front mech far enough out to clear the chain then it is a matter of tesion, if you can't get this with the barrea adjuster then shift to the smallest ring, remove all the tension from the barrel adjuster. set the lower limit screw so the mech just clears the chain on the inside, then loosen the cable pinch bolt and take up any slack, it doesn't have to be pulled tight, then retighten the cable pinch bolt. You SHOULD then be able to tweek the shifting with the barrel adjust on the shifter.
Even then front mechs can be a pain to set up imo.