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long_gutslong_guts Posts: 44
edited May 2014 in MTB workshop & tech

I'm quite new to this forum and I don't know why I didn't find it sooner, but anyway back to the problem. I recently upgraded my bike from 21 speed to 24 and I have a strange problem in that all the gears work fine, but when I'm in the middle cog on the front and any of the three smallest cogs on the rear the chain comes slips off the chainring. The only thing I can think is that maybe the front chainset isnt quite right or something? Any help or ideas would be grateful.

Many thanks



  • nicklousenicklouse Posts: 50,675 Lives Here
    which way is the chain coming off? to the frame of to the big ring?

    but is sounds like a worn chain ring.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • It's going towards the big chainring. Out of interest are the mega9 chainrings spaced closer together than say a standard/old 3 ring chainset?

    Many thanks

  • Chunkers1980Chunkers1980 Posts: 8,035
    Spacing is no different, it's just that chains got thinner so the teeth need a different profile.

    So - the spacing standard has not changed it's mech profiling and teeth that have.

    There's now dyna-sis which is the 10 spd, mega9.

    XT mega 9 M770 cranks are the same as dynasis 10spd, just with different rings.
  • andyeezandyeez Posts: 77
    Hi, I have some wheels to sell but can't PM from your wanted ad. Could you send me your email add so I can send you details. Thanks, Andy
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