Jockey wheey touching cassette teeth

[Yog Sothoth]

My wife has a commuter hack which has a 7-speed set up with a 12-32 cassette. Recently she needed a new rear mech so I put on a spare 9-speed Deore one. It works, sort of, but on the largest sprocket, the top jockey wheel is so close to the sprocket that the teeth of the two actually touch, making it noisy and notchy when riding, and also making the gear change difficult off this sprocket.

I've screwed in the mech positioning screw all the way but it makes no difference. Anyone know why this is happening? I'm guessing the 9-speed mech somehow isn't designed for the 32-tooth sprocket on the 7-speed cassette. Would buying an older, 7-speed mech sort it?

 

[Thias]

What is the exact type of the new mech? RD-M591 SGS (long cage)? Of so, it is capable of coping with up to 34 teeth. So that shouldn't be a problem.

I once had that same problem. I solved it by using a longer positioning screw. But its also possible, that the spring in the newer mech is broken or weak.. Then, that screw would have close to no effect...

 

[Yog Sothoth]

I'll have to check the model when I get home. Long cage though. The spring could be weak, perhaps: the screw has zero effect.

 

[xxnick1975]

chain length? too long?