After a bit of advice with some gear issues I'm having. I'm having trouble getting the rear mech to line up with the sprockets properly.
I've tried adjusting the tension, but it seems impossible to get it to work properly on all sprockets; if it lines up on the bigger sprockets, then there's too little tension at the other end of the cassette, and so I have trouble shifting between the smaller sprockets.
Conversely, if the tension's right for the smaller sprockets, then it's too high for the bigger sprockets, and the chain keeps wanting to jump up onto a bigger sprocket at the other end of the cassette.
Here's a really rubbish diagram of the problem (not to scale, and I have a 9-speed cassette but couldn't be bothered to draw that many
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):
Basically, the "spread" of the indices for the derailer is too large. I've tried adjusting the tension, and the H and L screws, but the best I can manage is a compromise, so that the derailer's not perfectly aligned at either end, but it just about works. I can still ride the bike, so it's not a show stopper, but it's very irritating when the chain keeps skipping when I shift, especially on climbs.
Any ideas?