Originally Posted by Briareos

I don't think a 7400 derailleur would take 10 speed cassettes? if it does...10 speed DA with mostly 7400 parts. I even got a stem, but JUST missed out of a 7400 headset.

Ok.

If I use a 9-speed shifterI can index 8 of them and either the highest or lowest gear becomes friction as long as the limit screws keep it from going too far?

Does the 7402 derailleur accept 10 speed cassettes?
If it can use 10 speed cassettes does that mean I can use 10 speed shifters, or will the derailleur not work?