I guess your in rock crawling land. My tank with a mix of city, highway, and boat towing is at 22. I'm running stock 32s. Post back after re gear it'd be interesting to see how much the mileage changes.
...and hand calculate. That's why it's called a "lie-o-meter", and that combination would be gutless with any elevation and anything remotely challenging outside of a mall parking lot.
Why? that would be a horrible gear ratio for the upper gears on the highway drives and for any semblance of serious off roading. What suspension lift do you have? Is this just a DD?