I am not very intelligent when it comes to rear end ratio's, and I was wondering what is the easiest way to find out what my ratio is. Also, what is the best ratio for low end and high end? I am trying to make my truck as fast as possible without hurting my normal day to day driving

 

You can find your ratio either in the drivers door panel, or on a small tag on the axle housing itself. Somewhere it should have the numerical value (i.e. 3.55, 3.31, or 3.08, etc.) followed by a LS for limited slip, or something else for normal ratio.

Lower gears (higher numerical value) give good, quick starts; they are good for towing, as they put more torque to the wheels. Higher gears (lower numerical value) provide better gas mileage, as they require the engine to turn less RPM's. They do not get as much torque down, so starts are slower. Theoretically, this would also mean a higher top end speed, but I believe that with a good engine, 3.55's will get you to the same speed, no questions asked.

-Flea

 

i don't know about everybody else,but i don't like the 3.55 in my truck,it's way too slow off the line,of course it is a 4x4 supercab.i'm gonna get a 4.10 for mine,but a 3.73(i think) is what alot of people on here have,so it would be a good compromise.if you have a regular cab a 3.55 would probably be good,but since i've never driven any new f-150 other than mine,i don't know about a reg cab.the 3.55 in my truck would probably be good for normal people though,i could drive a cobra r and still think it's too slow.