Originally Posted by
grahameinlondon
Thanks so much. But I don't understand how a 9 speed derailleur will work on a 10 speed? Where can I find the pull ratio for my ST6600 shifters?
The difference in pull
amount is in the shifter. 7-9 speed for road & mountain RDER's (with rare exception(s) you don't have to worry about) are all the same ratio.
As the number of cogs go up, cog spacing gets closer so the shifter pulls proportionately less.
The shifter is the master and the RDER is the slave.