Originally Posted by

**sjpitts**
Can you use a Shimano RD-6400 "600" rear derailleur with a 9 speed cassette? **Yes.** A 12-27 cassette if that makes any difference. From what I have read, I think you can.

And can also use any 9 speed shifter-- including the ultegra and dura-ace 9 speed brifters? **Ultegra, probably, and I've done it with Sora.**

*Dura Ace, not so sure, as it really liked to be matched to a 9-sp RD.From what I know, it's 7400-7400 and 7700-7700 and not adviseable to mix and match outside that. Others here will correct me, I'm sure. This is definitely the place to find that out.*

Again, I think the answer is yes, but I am looking for some confirmation.

What about the matching front derailleur? Will it work as well? **Yes.**

Jared