05-27-2018, 10:26 AM
I think your answer is in this thread: https://www.bikeradar.com/forums/viewtop...t=13015074
Basically, the amount the derailleur moves for each shift depends on both the shifter and the derailleur. The shifter determines the cable pull per shift, but the derailleur determines how much movement of the rear mech you get for a given amount of cable pull (the actuation ratio). The rear derailleurs for Shimano 8-,9-, and 10-speed groupsets all have the same actuation ratio, and so any of those rear derailleurs should work with any rear shifter.
Keep in mind, however, that while the 9-speed and below groupsets all have the same width chains and sprockets, 10-speed has a narrower standard.
Basically, the amount the derailleur moves for each shift depends on both the shifter and the derailleur. The shifter determines the cable pull per shift, but the derailleur determines how much movement of the rear mech you get for a given amount of cable pull (the actuation ratio). The rear derailleurs for Shimano 8-,9-, and 10-speed groupsets all have the same actuation ratio, and so any of those rear derailleurs should work with any rear shifter.
Keep in mind, however, that while the 9-speed and below groupsets all have the same width chains and sprockets, 10-speed has a narrower standard.