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So I've read the tech help and followed the youbube tutorials but I still can't get my rear mech to index properly.

At first I thought it must be a problem with the rear mech so I changed that, and in doing so I managed to cross thread the hanger and so replaced that as well.

However I'm still getting the same problem. The sympton is that (after setting the h/l screws) I set the tension so that it jumps correctly for the first change from the smallest cog to the next one up but then on the next change it jumps two, then nothing, and then I start cursing...  20

The only thing I can think to do next is getting a tool to ensure the hanger is aligned properly... but should this be necessary on an alu frame with a replaceable droupout?

Any suggestions would be gratefully received.

3 comments

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DaSy [687 posts] 5 years ago
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I know there was some issues with some of the Shimano shifters in 2009 I think, 105's I believe, whereby they used to have a region that would refuse to change properly, whilst still changing okay on gears higher and lower.

Don't know if any of that is relevant to your setup though...

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dave atkinson [6142 posts] 5 years ago
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Quote:

The only thing I can think to do next is getting a tool to ensure the hanger is aligned properly... but should this be necessary on an alu frame with a replaceable droupout?

it *shouldn't* be necessary but it's not beyond the realms of possibility either

my troubleshooting would probably go:

1) check that all the inner and outer cables are running freely, replace if necessary. you've replaced the mech, are the cassette and chain okay? if a particular sprocket is more worn it can cause the chain to jump, especially if the chain is worn too.
2) check that you don't have any slack in the cable on the small sprocket - if you do you may be setting the limit screw too high, which could cause the chain to jump on the second shift
3) erm, check your shifter and rear mech are the same cable pull? not trying to teach you to suck eggs, i've done this before and it took me ages to work out what was wrong  1
4) check the hanger isn't bent, best to get your bike shop to do that IMO, that way if it isn't you can get them to cast their expert eye over it.

good luck!

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TheHatter [770 posts] 5 years ago
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DaSy & Dave thanks for all the advice.

dave_atkinson][quote wrote:

3) erm, check your shifter and rear mech are the same cable pull? not trying to teach you to suck eggs, i've done this before and it took me ages to work out what was wrong  1

It's not a 105, its a cheap Sram set up on my commuter though the new mech I've put on is an Shimano XT that I thought was compatible so I didn't think it was cable pull as both the old and new mech are behaving in the same way.

The cables are relatively new but I'm beginning to wonder if I should replace the chain and cassette and cables now. I was trying to avoid this though as if I do the cost is mounting up and the bike may maybe not worth it...particularly as Wiggle have their Focus Cross bike at a very tempting 20% off a the moment...

Anyway I'll give all the above advice a go tomorrow. thanks very much!