Originally Posted by
bradtx
8S is 7400, 9S is 7700.
It's not nearly that simple. A 7700 hub will indeed work with 9S, but it also works perfectly with 8 and 10 speed.
7400 was around for a LONG time, going back to 6-speed thread-on freewheels. If I'm not mistaken only the 7403 rear hub was 8-speed Hyperglide (so also compatible with 9 and 10 speed.)