Posted by: tashi
My plan has been to use a 11 speed XT derailleur on there when the XT 10-speed with RADr cage needs replacing ‘cause apparently it works. Or complete AdventX.
I love franken-drivetrain talk!
I can verify 10sp Shimano shifters work fine with 11sp Shimano RD's -- theoretically a couple of the shifts will be off by the smallest of margins. I think I can find that when bike is on the stand, but on the trail it is indiscernible. 11sp RD's (and older M6000 Deore 10sp RD) clears 46t cog without issue and may clear up to a 50t with b tension turned in depending on hanger geometry and chain growth.
If you want to cobble together a 9sp clutch setup, you want the 9sp SRAM shifters with a 10sp or theoretically 11sp Shimano clutch RD. Shifts are close enough as is, and if you space out the cable attachment by about 5mm or so then cable pull is essentially perfect.
A Shimano 11sp shifter will supposedly shift a Shimano 12sp RD well, so by that thinking a 12sp RD should be cross compatible with 10sp Shimano as well and would give clearance to run a 50t. I haven't had to resort to testing these out yet though.
AdventX is also very intriguing to me. It's supposedly only compatible with itself, though I haven't found anything on the net about people trying the AdventX shifter with a Shimano 10sp setup. The shifter is cheap if it can deliver XT level performance. I especially like the 10sp 11-48 cassette, good range and spacing and very well priced. Option to save a bit of weight or save $20 and stay with the all steel cogs. I think the 48t will work well on my hardtail with the 11sp Shimano RD even.