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[Closed] Chain jump on trek remedy

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[#557889]

Everything appears to be perfect, lubed, clean, well set up and straight. All parts almost brand new, X0, Sram cassette, Shimano chain and XTR front mech and chainset. If I go for a quick ride on the road after setting up everything appears to be perfect but when I get onto the trails whenever I get to the lower half of the cassette the chain jumps and skips on the sprockets.

Anyone have any ideas?


 
Posted : 16/05/2009 5:35 pm
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Put it into the largest sprocket and see how close the top jockey wheel is to the cassette, if it's not fairly close then it's not going to have a good chance of controlling where the chain runs.


 
Posted : 16/05/2009 6:16 pm
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could be a stiff link in the chain. pedal backwards slowly and watch the chain exit the bottom of the rear mech.


 
Posted : 16/05/2009 6:53 pm
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Cable tension or stops are wrong. Bottom stop set to far out i think, undo the cable and pedal the bike, push the rear mech through its motion.
Check it dosen't go over the back of the cassette or run to low.
Arm should be just below the smallest sprocket but you'll see/hear if its over shifting


 
Posted : 16/05/2009 7:22 pm
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How new is it?
Could be the cables stretching a little causing the gears to not behave as they should


 
Posted : 16/05/2009 7:43 pm
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I have just reset everything, stops, cable tension, new powerlink etc etc so I will see how I get on tomorrow. I hope this will sort it but every time I have tried this it goes back to jumping almost as soon as I get out


 
Posted : 16/05/2009 7:59 pm
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Ed I was getting the same problem, I ran through the set-up, stops & indexing according to Sheldon Brown and sorted it out. The key seemed to be smooth transition between bottom two cogs.


 
Posted : 16/05/2009 8:08 pm
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Could be a bent mech hanger if it's only doing it at one end of the block.


 
Posted : 16/05/2009 8:09 pm
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Cable tension or stops are wrong. Bottom stop set to far out i think, undo the cable and pedal the bike, push the rear mech through its motion.
Check it dosen't go over the back of the cassette or run to low.
Arm should be just below the smallest sprocket but you'll see/hear if its over shifting

Sorry, but that has nothing to do with the OP's problem.

Out of all the responses, it either needs a bit of fine adjustment, or you have a bent hanger/worn mech.


 
Posted : 16/05/2009 8:12 pm