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Jumping gears

Hi , I have been having gear problems on my mountain bike , The rear gears jump when I put any power down. I had the bike serviced hoping that would sort out the problem and it was OK for a couple of weeks , now it has started jump again . Any idea's could it be a stretched chain? or a bent derailer (does not look bent to me).




  • MikeyBMikeyB Posts: 135
    It could be a streched chain, worn cassete, rusty cables, derailer that needs adjusting, etc. All things that should have been picked up when you had the bike serviced. Where did you get it serviced and what exactly did they do? Did they make any recommendations about parts that needed replacing?


  • They did change the gear cables , did not recommend anything else , I think I will pop back in , the shop was Bike Trax in brentwood. They have always been good in the past .
  • MikeyBMikeyB Posts: 135
    If the chain or cassette were worn and needed changing they should have spotted it. If they changed the cables it's possible they have just stretched a bit (I think they do that) and everything needs a little bit of adjustment again.


  • rpopper65rpopper65 Posts: 171
    Gear and brake cables ALWAYS stretch after you put new ones on.

    Look at the cable that is affected by the jumping and trace it all the way down to the rear derailleur, put your derailleur in the highest gear (which should have the least amount of tension on the cable), and pull on the exposed part of the cable. If it is not reasonably tight, like maybe you can fit several fingers underneath the cable, then the cable needs to be tightened. You can do this by (a) adjusting the tightening screws on your gear shifter to see if you can tighten up the gear cables until there's less slack (should still stretch out a little, as it should be at the lowest tension setting when you shifted gears before) or (b) actually tightening the cable itself (if you have the right tools, you'll probably need the right size allen key and a 'third hand' cable tool to keep the tension on the cable).
  • Cheers , I will take a look at the weekend
  • TheMonkTheMonk Posts: 10
    The first and only time i used Bike Trax they struck me as an unorganised bunch of Muppet's. I've spent hours fiddling with my bike, many hours invested in bike maintenance when i should have been out on the saddle. Follow the advice given, if your planning on having a tinker yourself then pop down the library and get a maintenance book out. In my mind learning how your bike really works is time well spent.
  • rpopper65rpopper65 Posts: 171
    Some places where you can find instructions on basic bike maintenance and repair:


    (they have a series of well-illustrated, step-by-step instructionson their site)


    (this is a PDF pamphlet with a couple of good, basic instructions and a few tips)


    (a few articles linked together (look at the index list of articles on the left-hand side of the screen and click on the "Click to Read It" link on the right-hand side of the screen if you see an article you want to read or print out - you'll have to register with them for free to read the articles)

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