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XTR M960 Rear Derailleur Tensioner?

cyprusgriffcyprusgriff Posts: 12
edited January 2011 in MTB workshop & tech
Hello everyone,

My rear derailleur pulley cage has developed a habit of rapidly springing forward and back by about 1 inch. This happens when pedalling on the front middle chainring and in any gear on the cassette.

The M760 XT cassette (9 spd) is not worn excessively and both pulley wheels are in good condition.
Gear changes are still crisp and smooth.

I've recently replaced the chain (HG73), and measured and cut the chain by the approved method then joined with a SRAM Powerlink. Both cage pulleys have been put back in their original positions.

Rear derailleur looks straight and everything lubed nicely.

Any solutions will be greatly appreciated :D



  • Chunkers1980Chunkers1980 Posts: 8,035
    I'd wager that to be chainsuck.

    Sheldon's pages will help you sort it.
  • Cheers Chunk,

    I think your'e right, chain suck is the most likely cause.
    I didn't even think about the front chain rings :roll:

    If anyone else is suffering with this, there is an excellent article about chain suck by Jonathan Levy.
  • Chunkers1980Chunkers1980 Posts: 8,035
    No probs. New front ring should solve it. What cranks do you have?
  • nicklousenicklouse Posts: 50,675 Lives Here
    or a stiff link.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • No probs. New front ring should solve it. What cranks do you have?

    Shimano M760 XT's.
  • nicklouse wrote:
    or a stiff link.

    I just fitted a brand new chain :shock: I'll double check though, it may prevent me from splashing out on new rings etc.
    Thanks for the tip :D
  • Chunkers1980Chunkers1980 Posts: 8,035
    Yeah - the reason I did not think it was that was the fact it's new and you use a powerlink - it's usually the Shimano joining pin areas that cause stiff links.

    Back pedal with bike upside down or in stand and look at the way the chain routes round the mech - it should be smooth with no notches.

    A steel deore middle ring are cheap and long lasting for about a tenner.
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