i just bought a used truck with a 6" lift and 35" tires. its a v8 5.0 4x4 92 f150 extra cab. i don't think it has been regeard to account for the big tires. how do i tell if it has?

also, i get about 10 miles per gallon at worst, 11.5 if i drive like a granny, is this the best i can expect? can other things help besides driving habbits? and with the gears, what does that do exactly for performance and gas mileage? what gear ratio do i want, how do i find out?

thanks. as you can see i am new at all this.

see a picture here:
http://phoenix.backpage.com/binary/f5d/1091761234--truckJPG--full.jpg

 

well the only way i know how to check to see if your gears have been changed is to take off your diff cover and count the teeth on your ring and pinion gears, your gas milage seems to be about normal i would say i get about 11 to 10 mpg with my mods and mine is brand new

 

there is a way to count one rotation of the tire to how many times the drive shaft turns....dang, I can't remember exactly, but hopefully this jars somebody's memory..

I think you gas mileage is pretty normal as big truck 311 said.

 

First jack up the axle and then mark the pinion and the tire. Turn the tire one full revolution and count how many revolutions the driveshaft makes. The more the driveshaft turns the deeper the gears. As an example 3.73:1 gears mean 3.73 driveshaft rotations to 1 tire rotation. With 35s you're going to want to go with at least a 4.56 gearset or you will be rebuilding the trans before too long, been there done that.

As far as mileage goes, you're pretty well stuck with what you're getting now. The lift and bigger tires are whats hurting you and the only fix is to remove it. There aren't many mods out there that will increase your mileage, but for what you will spend on those few that will you will take ALOT of miles to recoup the cost of said mod. Best thing is to baby the driving habits.