Gravel Mutt: Trek 830 into a gravel grinder?

Wondering if any of you have had much experience turning a MTB into a gravel bike. I've found a Trek 830 on CL for $160. Ever since Guitar Ted's series on Gravel Mutts, I've been hunting for a candidate to hack into a respectable ride. I think I might have a winner here. 

 

My current bike is a steel road bike w/ 27" wheels, which seriously limits my tire choice. I'm looking to produce a robust bike with some lower gearing and the ability to put some wider tires under me. With a MTB geared like the Trek, the biggest modification would be putting on some drop bars and changing the necessary brake and shifting levers.

Some details: I ride in NW Iowa, gravel here is hard pan with rocks <3/4". I'm 6'3", 220 lbs and prefer to ride in the drops. I rarely get going faster than 20 mph on flats, so that's my spin out limit. I'm a terrible climber looking for some friendly gearing. I'm registered for the Almanzo 100 this spring, this bike would be built with that ride in mind)

-Are there fit issues with putting drops on a MTB? 
-With converting to drops, any weird compatibility issues with stem or handlebar? I'm part timing at a bike shop that has a pretty deep parts bin for bikes of this age.

In short, what has worked for you?

The usual challenge with drops on a MTB is that the top tube will be longer than a road bike's. You'll need a stem that is a good deal shorter and/or higher to get a good fit.

Next is that this bike might have a 1 1/8" threaded headset, and you won't find any road stems in that size. That means you'll have to use a mountain stem and find drop bars that have a 25.4mm center section. You can sometimes cram a 26.0 road bar in a mountain stem but handlebar failures can lead to expensive dentistry.

It may be that you can't get a short enough setup with drop bars. You might be able to find something comfortable with a bar that mostly sweeps backwards like the Velo Orange Postino. You can wrap it with handlebar tape like a drop bar to get some more positions.

The gearing on that bike is probably a standard 74/110 crankset with something like 28-38-48 chainrings. The granny ring can go down to a 24. Or you could switch the cranks out to something with a different chain ring size and all your rings will be smaller. You will probably need a different bottom bracket if you go to a more modern crank.

The rear cassette is probably 7 speed and I'd guess a 13-28 or so. Shimano still sells 7 speed cassettes that have 30,32, or 34 teeth so you have options to go lower too. You may need a longer chain, depending on the changes you make.

If your road bike uses a short reach sidepull, you also might consider changing the wheels on your road bike to 650b. If not, switching to 700c could give you more tire choices as long as they clear the frame. If the only tight spot is between the chainstays, it's pretty easy to crimp them a little to gain clearance.

Just try to find a multitrack in the same price range.  My frame/fork came with fenders, a set of pedals and some tires for $30.

 

It can  be done.

 

Other people have spoken to the fit and conversion issues so i won't address those.  I'm primarily a pavement rider but I'm looking to get into dirt/gravel riding.  I have a 1995 Trek 820 that is very similar to the one you posted.  I will say that it rides very similarly to the Surly Troll I test rode, and that was with near slicks on the 820.  I think with some tacky MTB tires, the rides would be almost identical.  If the fit and compatibility issues can be overcome, I think the 830 could be a fine dirt/gravel bike.

I also have two mid-90's Multitracks and their geometry is very much that of a mountain bike except their top-tubes are shorter than the MTB's of that era.   Back in the 90's I used to ride one on gravel and dirt roads on a regular basis with no problems.  My only complaint is that tire size maxes out around 40mm.  That wouldn't be a problem for many riders but it is for my particular circumstances.  I'm currently looking for a bike that will allow me to use real MTB-size tires.  That's why I bought the 820.  

 I set up a kona explosif and used an adjustable Giant stem with 1 1/8 quill and albatross bars so i dont have any long top tube problems. the stem is pretty short reach so it would work with drop bars too. I have 26x 1 1/2 tires that work well on tarmac and gravel. next set will be compass 26x 1.75's. see below.

what a gorgeous all-rounder!!

I really like the Trek 700 and 800 series from the early 1990s for conversions for a variety of uses. My gravel grinder is based on a 1993 Trek 700. I left it flatbar with Ergon bar ends, but Problem Solvers is a great resource for finding the parts you need to make all kinds of adaptations, including handlebar shims.

http://problemsolversbike.com/products/handlebar_shims/

I've used a shim on my road bike for a couple of years with no problem. They actually spread the clamping force over a slightly wider area of the bar so I don't think there should be any trouble with stressing the bar and I've never had mine slip.

Good Luck on your project.