I want to get a shadow plus mech to reduce chain loss but can’t afford, and or be arsed, to change the whole bike to a 10spd. It occurred to me that the indexing of a derailleur is determined by the shifter not the mech it’s self.

Has anyone tried a 10spd mech with 9spd shifter anc cassette?

Just thought 9spd chain might be too wide……

Its been done and doesn’t work i have just upgraded for the same reason to 10sp.

The 10 speed mtb mechs need a different shifter pull ratio to 9 speed so won’t work.

You don’t need to change everything, 9spd cranks and chainrings will work with 10spd. You just need rear mech, rear shifter, cassette and chain (providing your chainrings aren’t too worn)