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Hi my gears are jumping on my carrera tdf when i click my leaver to go to 4 it goes to 4 then seconds later it jumps to 5 ive just replaced my cable and everything else is working fine.
Check out Park (or others) videos on gear adjustment.
Your mech might be worn.
http://www.parktool.com/blog/repair-help
Follow the method on here. If that doesn't work then something else is wrong. It works flawlessly with new kit in my experience.
Things to check (in order of likelihood)
Wonky wheel (is it in straight)
Worn mech, pivots or jockey wheels - look for excessive play.
Bent hanger
Worn chain
Worn cassette
I concur with the above. If your cassette and chain are worn, for example, you can spend all day adjusting, indexing, fiddling with cables or whatever, and it will just never work...
New kit will normally index fairly easily. How many miles has it done?
Also, check that the dérailleur hanger is straight. Could easily be knocked out of alignment, even on a new bike, and cause issues.
thanks for the replys its done 500 miles + since i bought it seccond hand so the cassette is prob worn