Originally Posted by
BigAura
It may work, but I'm guessing it's not the buttery-shifting of the matched group-set. STI shifters are rather finely made, tightly spec'd, and optimized to work in conjunction with their matching derailleurs. If you're adamant about STI I'd stick with matching levers and derailleurs, especially for a new build.
I have 5703 brifters coupled with a 9 speed XT M772 RD on an AWOL and it shifts every bit as good and maybe a little better than the X0 Rear Derailleur with Doubletaps on the Vaya. Been running the setup for over 2 years now... As for a mountain front triple, I never did get it setup satisfactorily but have a few new ideas but the daughter likes the 5703 triple on the front so I'm leaving it be.
The thoughts for the front triple setup are as follows, shim the mountain triple chainline using shimano road bike instructions, not the mountain. Or use a braze on derailleur couple with an Sram wide spacing adapter.
SRAM Wide Spacing Braze-On Adapter > Components > Drivetrain > Front Derailleur Parts | Jenson USA
or both
To compensate for the chainline differences between mountain and road triples...
To reiterate, the rear derailleur will work like a champ for sure. The front setup is pure speculation on my part as I run a road triple on my bike.