As with many vehicles, your fuel economy will depend greatly on your driving style. If you're one of those types that absolutely has to be the first one to reach the next stop light, you'll pay for it. Accelerate as slowly as is reasonable, and maintain a steady cruising speed. My '85 pickup (22R, standard cab) and '89 4Runner (22RE) average in the low 20 mpg range (mostly city driving). Both are 4wd, 31" tires, stock gears, no lift.Looks like 15 - 18 pretty much covers it - unless you buy something with some crazy 4.56 gears or something... then hello 12!