Platinum T.C.

Depending where you live a 3:31 axle F-150 would be harder to re-sell.

I've owned 3:55--3:73 & 4:10
My last one, a 2012 FX-4 came with the 3:73. My 2001 & my 2014 Lariat both have/ had the 3:55.
Between the 3:55 & 3:73 there is no noticeable difference in gas mileage.
I doubt there would be a noticeable difference between 3:31 & 3:55?
I've never driven a F-150 with a 3:31 or would I want one.
If I had the choice the 3:73 is the best way to go. My 2014 4x4 Lariat happen to have the 3:55 & I've had it before.
The 4:10 was on a 1986 F-250 with a 351 H.O. Tons of Power, the mileage was so-so.
Please remember when purchasing a F-150 or any Truck. Gas Mileage really doesn't matter that much. If it did you shouldn't purchase a Truck. Stay with a Station Wagon.
Only my thoughts.
Don't want to make any Enemies.

2talltechie

Yes, probably too sluggish. 3.15 would be really bad. Or would it...

Billy Mulek

My dad as a 2013 EB with 3.31 and I have a 2014 EB with 3. 73 he is averaging 1 might better than I am.

2ndchance

So on a 26 gallon tank, you can go 26 miles further? How much gas does this save tank after tank? Can someone smart on here please do the math for us? Thanks.

packplantpath

Lol. 100 tanks= 2600 miles, 50 tanks is 1300. If you are running them dry every time. Bad idea!

So figure 20 miles per tank extra with a 26 gallon tank. Reasonable. If you get 500 miles per tank then you get a free fill up every 25 tanks. Buy 25, get one free! So it would save a person who drives 15000 miles per year (30 tanks) 1 tank of gas or less than $100 depending on gas price.

So, why care so much about 1 mpg?

2ndchance

So imagine thousands or hundreds of thousands of vehicles getting 1 mpg better. I'm thinking that's where it really matters. Thanks for doing the math. You can send me an extra $100 anytime!

Hardlymoving

Between my brothers and I we have mostly identical F150's except for the axle ratios (3.31, 3.55, 3.73). All three are 2014 Ecoboost SuperCrews, same size tires, 4x4's. Convention wisdom would lead one to believe that the one with the 3.31 axles would get the best mileage but it does not. I realize that there are so many other variables that one cannot come to a conclusion based on just our experiences but it is interesting just the same. In fact the one with the 3.73 ratios seems to get the best gas mileage but he lives in a high altitude location (5400 ft) so that may account for that. I have the 3.55 gearing and I get better gas mileage than the 3.31. Statistically I think there may not be much difference between any of the axle ratios but one may notice a difference while towing or hauling heavy loads.

Dan M.

I believe the only way you could tell if a 3.55 was quicker than a 3.31 would be to floor it on a drag strip. Driving it normal around town or the highway, there's no way.

Dan M.

You'll be fine with 3.31, not only on the highway but also around town. I get 18 mpg in town and 24 on the highway if I keep it a little under 70.

2talltechie

Here's what I figure looking at it slightly differently.

Suppose you get 20 mpg and your friend gets 19 mpg, and you both initially get 20 gallons each in your truck. Your friend will be losing 1 mile per gallon as compared to you for each gallon in the tank. That means when you each run out of gas, your friend will be 20 miles behind you (1 mile for each gallon), and will have to purchase a little more than a gallon to catch up to you.

That means it is costing your friend (or saving you) about a gallon of gas for every 20 gallons you use up. Two gallons if there is a 2 mpg difference in the two trucks.

If you put 20 gallons in the tank every week, that is like 52 free gallons per year (52 week in a year). At $4/gal, that is over $200/year. If I ever get an annual $200 rebate, I will gladly take it.