Originally Posted by
roccobike
FYI, for the future, I'm using a RSX long cage with 9 speed 105 brifters and everything works fine. If I upgrade that bike to 10 speed, I won't be trying the RSX unit but that's becuase I have other derailers.
I would expect the 7-speed RSX rear derailleur to work with 9 or even 10-speed shifters and cassettes. The OP's problem is his rear hub and a lot of other things aren't compatible with >7-speed.