My new tourer/brevet bike. Works rather well but I have one niggling issue. The previous owner fitted SRAM X9 on the RD, and shifters but not the front leaving a 9 speed Shimano 105 there. Chain rings are deore triple with a hollowtech bb and 26 38 48. Heres the issue. It shifts great in the back - you would expect that being matched and SRAM shifts very nicely indeed. But at the front on the upshift it works but is less than positive. Never played with SRAM stuff but I suspect its shimano/sram not playing nice. Downshift is instant. Checked the specs on the x9 FD and I see its only rated to 44. I won't ride with a 44. Do the SRAM road FD series work with the mtb deraillers or do they do the same as Shimano? I think if I match the shifters which are very nice to the right derailler I should be able to solve this trivial little problem.

The front and rear derailleurs operate completely independently from each other - one has no impact on the other - just to get it out of the way. In the front, it should be possible to make any shifter to work with any derailleur. This is because you tune the derailleur extension for the middle ring by tensioning the shifter cable and the extensions for the inner and outer rings are regulated with the stop screws on the derailleur. The outer ring rating of the derailleurs has some but not critical impact on operations - you can get the derailleur working no matter what that ring is. (Size difference between middle and outer may matter, if it too small, but then the derailleur gets blocked which does not seem to be the case here.) Excellent instructions for novice front derailleur adjustments are provided on the Park Tool site.