Just trying to save some cash as I have the xt mech in my spares box. Any advice appreciated?
Might help:
[url= http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/dyna-sys-10-speed-compatability-9-speed-shimano-systems-646014.html ]http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/dyna-sys-10-speed-compatability-9-speed-shimano-systems-646014.html[/url]
Not if they're 5700 (hidden cables) STIs, if they're older ones then you can.
My 5600 worked fine with an XT and now SLX 9 speed front mech.
It's unlikely to work unless you have old STIs. IIRC road STIs have used a different amount of cable pull for the front mech for the last few years, which makes road STI with MTB front mech and vice-versa incompatible. I tried it recently with tiagra shifters and a deore mech, but had to go out and get a sora mech. Also IIRC, as of quite recently shimano have done the same to the rear mechs.