should i change gears?
 

hi, i have a 01 f150 supercrew 5.4L 4x4 w/ 6in suspension and 3"BL. i'm not much of a mechanic or anything but, i'm wondering what kinda gears should i get in my truck. right now i'm only running 315/75/16's with 3.55's in the back. hopefully i'll get bigger tires soon. right now i only get like 9-10 mpg and that's me baby'ing it. And i'm wondering how much will my mpg change if I get like 4.10's or 4.56's. I don't really do any highway miles, mostly to and from school, like 10 miles. Oh, and one more question, how much damage will 2.55's in the front and 3.55's in the back do to my truck, when mudding of course... I was told that as long as all the tires are spinning it would'nt hurt TOO much... Thanks alot for looking. ~ Mitch

i would go to 4.56 especially if your going to go w/ bigger tires, your torque converter will thank you. , how could you have 2.55 in the front and 3.55 in the rear. i would not run any ratio that far off in the mud or not Tcases are expensive.

First Since you arent doing any highway miles then go with 4.88's (prepare for 37's+)

Its gonna cost around 1500+

Also your gears have to match front to rear to beable to use 4x4. Theres a certain degree that they can be off but its not very much at all.

I agree with Trimble, if you are not on the highway alot go with 4.88's. I run my truck on the highway alot with 35's and the gas mileage is not really that bad keep it at 70, 75 at max. anything over 70 and you feel a very noticeable hit to gas mileage.

I have 6in susp and 3in body and run 37's with 4.88 gears. I'm also unlucky enough to have a 4.6 so i need everything i can get to make it think i have a little power. 4.88 is good if you want 37's or bigger tires. I could have gone with 4.56 but the 4.6 has 0 power

Thank you everyone, also eliminate i'm currious if your tires rub at all on your truck? I think that the person that had my truck before me was running 39.5's but they were rubbing pretty bad. thanks. ~ Mitch

No rubbing as of yet. I could have gone with 38's and trimmed a little on the front valance. I could probably make them rub if I get it arched up to much though.

ok thanks alot.

i run this same set up with 37's and mine do not rub at all in any postion. they did rub the bump stop on the lower control arm but i just cut those down. need to make sure you use 4.5" bs