I have a 95YJ with a 4cyl, 5speed. I get around 17 mpg with 31-10/50 tires. I drive it daily to work. 10 miles interstate, 10 miles curvy mountain blacktop, 6 miles steep,muddy,rocky,or dusty if it has not rained mountain road. The only time it feels weak is when I first hit the interstate which is about 3 miles up hill. I dont shift to overdrive until I get to the top of the mountain. My Jeep might do better with smaller tires but I'll probably keeep the ones I have till they are worn out. Hope this helps. <img src="/forums/images/graemlins/patriot.gif" alt="" /> <img src="/forums/images/graemlins/patriot.gif" alt="" />