Originally Posted by
HillRider
You will need new shifters and new brake levers since brifters made for drop bars have the wrong size clamps. Also, you will probably need "flat bar road bike" shifters as MTB front shifters aren't compatible with a road front derailleur although, with a double crank, an MTB front shifter may be workable.
You will also probably need a new stem unless your new and old bars have the same clamp diameter.
This is incorrect. Mountain "trigger" shifters and "flat-bar" shifters are 100% interchangeable. In fact, there's two bikes in my garage right now, one with "mountain" shifters and one with "flat-bar" shifters and otherwise identical setups. They work exactly the same.
The difference between (Shimano) "road" and "mountain/flat-bar" shifters is that the "mountain" shifters pull more cable. This makes it tough for them to work properly with "road" derailleurs on triples. The OP may be able to get mountain shifters to work with his current front derailleur, but the best solution is to use a "flat-bar" front derailleur, like a Shimano FD-R440 or FD-R770. These are set up to work with the long cable pull but the cage is designed to work with larger "road" chainrings.