The Conversion: Let's get to the nitty gritty here. I've given you all the necessary back round information, now let's see what it normally takes to retro-fit some drop bars to a standard mountain bike frame. I am using this Karate Monkey of mine as an example. This will be its second conversion to drop bars!
<===Here is where my stem and bars were to start with. It was a fairly upright, relaxed position for sketchy weather riding fixed. Nothing I would normally use for off road, but I am going with it as an example here. Many folks think that you need to compromise and go a size smaller or with some frame that happens to have a shorter top tube to retro-fit off road drops to it. I say "hogwash!" You can use the very frame that actually fits you now. The way a drop bar is properly fitted to a standard mountain bike is all a function of the stem. Let's say I really like the handle bar/grip position shown above. How would I get my drop bars to work and not mess that up?
<===Take a look here. I have zip tied the drop bar just below the grip section of the original bar. The drop section just under my ergo grip there is where I should have my hands the majority of the time I ride off road. If you draw an imaginary line from the red cap on top of the steer tube to just above the center of the drop bar, you will have the rise and reach of the proper stem to get your hands in about the same place in orientation to your saddle and front axle as you had with the flat bar or riser bar you are currently using. No changes needed in your frame. You can ride the same rig you love, just with a change in the stem and handle bar. Sure, you may need a custom stem to get the job done, but that's a lot cheaper than a custom drop bar frame and will still fit you like it should since you are using the same frame. Again, some will balk at this because of the "goofy" stem necessary to pull this off, but it isn't about looks! It is about function: Better feel, better climbing, better comfort. If that trade off is appealing, then drop bars will make sense regardless of looks. As it should be.
In my example, you may recall that I said the bars were not really where I would have them for off roading. I actually would get them about two inches lower, which accommodates a Salsa Moto Ace 40 degree rise X 90mm stem that I purchased for the job. In a follow up, I will present the way I accomplished my drop bar conversion using that stem, some Gary Bars, some old Shimano SLR aero levers, and some Avid BB-7 mtb brakes. (Yes....I know you are not supposed to use those levers with those brakes, but.......it works!)