Originally Posted by
jtravis
I guess the question is, would a derailleur built for an indexed application work?
Derailleurs don't know whether the shifter is friction or indexed.
A problem you might encounter, though, with a newer derailleur built to travel across 9 or 10 cogs is that you may not be able to set the limit screws for the relatively short travel of 5 or 6 cogs. You might have to modify the limit screws by using longer ones.