rim size, rear axle, body drop, effecting gas mileage

i get around 28 mpg out of my ranger when i had the 20s on teh rear... stock rear end ratio tho.

I have the same rear end, and I get 22 miles to the gal. I would check your fuel to air mixture . if your truck smells like gas when its running, thats probably the problem. its using to much fuel.