11silverbullet

ok, first off, I bought my truck used. its a 2011. 3.7, crewcab, 2WD, its got 14k miles. Now I bought it and it already had 22" wheels. They look pretty good on the truck. Now, I have gone through 2 tanks of gas and I cant seem to get over 13.2 MPG and I have been very gentle with the throttle. So I know and have read that the WIDER the tire, it creates a loss of fuel economy. and the LARGER the wheel does aswell. So I was thinking of swapping tires and wheels to help my MPG but I dont want to lose the aftermarket look. SO...
Does anyone know the specifics on how much a 5-6lbs weight savings PER wheel will do? It will be almost identical overall diameter of the tire from the 22" to the 20" .. Anyone know? SO pretty much the diamter will be the same, but the tire will be THINNER and the wheel be 5-6 lbs lighter too..
Anyone an expert or have experienced this change before? How much would I expect to gain back?
Also, before anyone asks, the swap will be free to me, Im exchanging the 22" wheels I have for the new 20"s the shop is offering me, so this is not going to cost me anything, but if there is no difference, well, I like the look of the wheels I have now. the tire size will be a 275/55/20 now If I remember right, I believe it was the same size as the pirellis the stock 20"s on the F150 FX2 come equipped with.
thanks for the help guys.

f150man3.5

How about some pictures of said wheels..........

Kenferg1

Get the brand and the tire size. Go online and find out what the tire weight is. Adding a lot of rotating mass will jack up your gas mileage. Lighter tires=better mileage as a general rule. Also, consider what your diff gears are (3.31, 3.55, 3.73) as that with larger tires can impact mileage as well.

11silverbullet

The diff is stock 3.73
I currently have Goodyear Fortera SL Editions size 305/40-22

ggallant1

is your mpg hand calculated or from the trucks computer? The truck may have never been adjusted for the larger wheels.

11silverbullet

I got it redone for the revs per mile for the new tire size at the ford dealership
And actually I have always been very religious on checking fuel economy since my older trucks without the cluster doing it for me. And it's only usually off by 2-3 tenths per gallon.

Kenferg1

They weigh 42 pounds. Max air pressure is 50 psi. Do you have them aired up? I had Fortera triple treads on my 05 Pathfinder. My mileage dropped almost 2 mpg and they only lasted about 30k miles. They were nice tires bit too soft to last anywhere near 50k miles like the stock BFG Long Trails did.

11silverbullet

I have them aired up to 40 psi.
I think I'm going to downsize to some 20" wheels that are lighter and some slimmer tires too. Our shop truck, which I didn't even know had a 3.7, gets beat up around town all day, has tons of idle time and I just looked at the mpg on the cluster and it says 15.7!
So it has to be my wheels causing this lopsided mpg I'm getting.
I'm down to 12.7

11silverbullet

With the wheel choice and tire I'm looking at getting, I'm going to drop about 15 lbs per wheel/tire combo. So 60 pounds total static weight but I'm sure that should translate to alot more rotational weight

yokev

Try to get a hold of a stock wheel and tire and weigh it. If you have a decent set of wheels, they should be 'relatively' light. If they're forged(aluminum), they'll be a WHOLE lot lighter than stock.
In any event, assuming you're lighter than stock(and you're the same height), the only other factor that will affect your mileage will be drag. Obviously the stickier the tire, the more drag it creates. You can get an idea of what you're looking at by looking at the traction rating(letter), and the treadwear rating(3-digit number.The higher the rating, the harder the compound= longer life)
The 'stickiest' DOT tire is gonna be rated 'AA'. The 'slickest'(lack of a better word) will be a 'C'.
A tire with say a '150' treadwear rating is gonna have the relative 'softest' compound, while a tire with a '500' will have a hard compound.
Unfortunately these numbers vary from manufacturer to manufacturer, but generally speaking, to maximize your mileage you'd want a 'C' and a '500'(or higher if they make 'em)
They do make 'low resistance' tires now days as well, which are specifically designed to have a low rolling resistance- which raises mileage.