"You can run the Zee on a 9spd setup, by using a 9spd SRAM shifter. I'm running an X9 shifter with the Zee on my miniDH bike, 9spd cassette and chain, and it works perfectly."
"It works because the ratios are really close (I think the difference between both is somewhere around 0.03). I haven't tried this on a 3x10 or 2x10 setup, where crossing the chain might put some more stress. I just know that for a 1x10 setup, all 10spds work perfectly"
" I can vouch for this as I did this on my 1x9 AM rig too. X9 9speed shifter, XT 11-34 9spd cog and Zee RD. No mods needed. Worked great and had no problems when I raced it last December."
" If you want the shifting to match up perfectly you can mod the ratio very easily with a 1/4inch square washer. It sandwiches in between the cable and the derailleur. You'll need a slightly longer bolt to accept the thickness of the washer. This gets the shifting near perfect. What Ploutre suggested is close but this will get you the rest of the way there. I'll upload some pics to my profile. I run it on all my bikes now. Big thanks to the man on MTBR who clued me in to this mod.
I forgot to add that the washer has a slot filed into it to accept the cable and keep everything lined up. This is important. The actual thickness to the bottom of the groove is .236". A hair less than 1/4""
"0 speed shimano DynaSys's actuation ratio (used on the 10 speed Deore, SLX, XT, XTR, Saint and Zee) is virtually identical to the SRAM ESP 1:1 ratio used on their 8/9 speed drivetrains over the past decade (from their original ESP models thru the X5 to X.0 groups), the difference is so minor that you'd need to shift 12 or 13 gears at the spacing of a 10 speed cassette before you'd notice any hesitation in the shifts. This has been known on the mtbr drivetrain forum for nearly a year now.
"
"10 speed shimano DYNA SYS rear shifters and derailleurs... = virtually identical ratio to SRAM ESP/1:1 9speed shifters and derailleurs.
9 speed shimano shifters are NOT compatible with any derailleurs except 9 (or lower) speed shimano mtb derailleurs, and all the shimano road derailleurs except for the 7 & 8 speed DuraAce ones (which you're unlikely to encounter anyway)."
http://www.pinkbike.com/video/295848
