I'm struggling and need help!

My front derailleur which is 3x9 speed got damaged. Shimano Acera 9-speed, 34.9mm clamp, low-mount, top-swing, dual-pull

but I'm thinking to upgrade it with a Shimano XTR M980 3x10, top swing, dual pull, 28.6/31.8/34.9mm

Would it be compatible with my rear derailleur 9 speed?

thank you for helping

  • Unless your buying XTR at Acera prices (Entirely possible given its a front derailleur), Acera to XTR is a waste of money.
    – mattnz
    Commented Apr 17, 2020 at 20:47

1 Answer 1


Front and rear derailleurs have no interactions, so there's no concept of direct compatibility between them.

Rear derailleurs have to be compatible with the rear shifter, cassette, chain. Front derailleurs have to be compatible with the front shifter, crank and chain. Obviously there is some interplay between the front and rear drivetrain.

I don't think that a 10 speed triple derailleur will work well with a 9 speed triple shifter and crank. Shimano changed actuation ratios (ratio of cable length pulled to cage movement) on 10 speed MTB groups.

I'm not sure that an old M980 derailleur from 2010 is really an upgrade anyway. Any benefit of a better front derailleur would be completely masked by the performance of the lower level shifter. Safer to get a current Shimano 3x9 Alivio or Acera front derailleur replacement.

  • I want to thank you for your quick response and so specify detail you have given me. you have no idea how helpful has been your answer. I will take your advice straight away. Commented Apr 17, 2020 at 16:24
  • @EduardoDelgado glad to help. You’ll find the community on this site responds quickly and has a large collective knowledge Commented Apr 17, 2020 at 16:54

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