Originally Posted by scrambledwonder
Hello there,
Will an old seven-speed thumb shifter set in friction mode work for a new 9-speed cassette?
Yes, but the sprockets are so close together that you may find the shifting a bit finicky.
Hyperglide is generally a bit dodgy with friction shifting anyway, because it doesn't give audible/tactile warning when the derailer isn't quite lined up with the sprocket.
Sheldon "Friction? No Thanks!" Brown