Are Ultegra brifters compatible with 10-speed XT Dyna-Sys derailleurs? Possible Duplicate:
  Road Shifters, Mountain Rear Derailleur?  




I'm looking to build a hardtail mountain bike with drop bars for commuting, touring and some occasional light off-road adventures.

Are 10-speed Shimano brifters like the Ultegra ST-6600 compatible with the 10-speed Dyna-Sys XT derailleurs?

Thanks.
In a word, no. Different cable pull ratio on both systems. You can check out this question if you want a slightly more verbose answer.