I'm trying to upgrade my cassette for lower gearing on a Nishiki Continental. The previous owner put on a (NOS) Shimano XT rear derailleur. I use friction shifters.

I looked on the back of the cage and the models says RD-M739. The document from Shimano says 32T maximum. What do you think, would a 34T 9-speed work?

I would like to have a bigger rear cog so I'm asking just to be sure it's not a RD-M739-SGS. How can I tell? Would SGS be stamped on the back if it would be?


RD-M739 front RD-M739 back

Update: I actually found a 7sp overdrive with a 34T largest cog on another bike that I tried. Seems to work just as fine as on the bike it came from.

Overdrive 34T with the XT RD

  • 5
    Offtopic, but the chain on the first photo looks incorrectly routed through RD cage. Commented May 21, 2018 at 12:40
  • Yes. It was when i got it (and took the pic). It's fixed. Thanks!
    – Ola
    Commented May 22, 2018 at 8:50

1 Answer 1


I just mounted the 34t cassette and it works fine.

I also tried it on an even older but same length DX derailleur and it worked there as well. Only using it for road and not MTB. Not sure if that makes any difference.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.