If I changed my gearing would I get better gas mileage? I have a f150 reg cab 4x4 4.6 running 35" tires. I have got a catback, air intake, and the edge programmer. Would gears give me better gas mileage? If so what do I need to get?

 

Assuming you have 3.55's now and the factory tire diameter was roughly 30", 4.11's would put you back to stock specs. If I were doing a gear swap, I would go for 1 ratio lower (numerically higher) so 4.30 - 4.56 depending on what is available. This would give you more torque however you will turn higher rpms at highway speeds, a trade off that I would take. So, the gas mileage question. What I saw when I went from 4.10's - 5.29's on a previous truck: Much better acceleration and slightly better mpg's in all driving conditions, slightly being the key word. You will not likely own your truck long enough for any mileage gains to offset the cost of your new gears, especially on a 4x4.

But, going from 3.55 to 4.56 would put a huge fun factor into your truck as far as overall driveability as well as reducing stress on the drivetrain theoretically reducing maintenance costs over a long period of time. So, 4x4, you can figure at around $1000.00 for gears and installation labor. Then, while you are in there, you might as well get a limited slip if you don't already have one....Open up your wallet!!!

 

That is very interesting. Good post. Answered questions I didn't even know I had.

 

Thanks for the help!

 

fun factor is a great word to describe it. I just went from 3.73 to 4.56 ( have 33.6" tires ) and the 0-80mph launch will put a grin from ear to ear on you. I may go with 35" tires when they need replacing but for now, this is way too much fun. I went with Yukons ( 9.75 rear and 8.8 rev cut fronts ) from Randy's Ring and Pinion. Between the gears, master install kits, for front and back, and a Mag Hytech diff cover, I topped $2000.00 when it was done, including gear oil changed after the 500 mile breakin period. Best 'seat of the pants' mod besides the tuner/intake combo.

 

Interesting....

Question for you, have you driven conservatively enough to know how many mpgs you get with the 4.56s and the 33s? Driving with a light foot?

thanks!