gas mileage with 31" tires

I plan on putting 31 on my truck soon just wanted to know if any one new the difference I will get in mileage I currently get about 23mpg with stock tires and rims. I will be keeping my steelies (factory) with the 31's. Any help?

 

What is the stock size for your truck? 4wd, prerunner, or 5 lug?

 

215 75 15, 5 lug its a 2wd I'm probably gonna be putting on a 2 to 3 inch lift as well

 

Well, I would expect you would lose 3 or so mpg. Maybe more with the lift. I am running 245 75 16s on my 5lug and get around 24 to 25 mpg, some times 26 or 27 if its alot of highway, but the new wheels are tires are lighter than the old. Pay attention to the weight of the larger tires and you can maybe save some gas.


Also, check out the tire size calculator at the bottom of thd page. It will help you figure the difference in sizes.

 

Thank you I will keep that in mind when I'm finding the tires I want. Do u still run stock rims?

 

I swapped the steel stock ones for a set of 16s off a 1991 nissan 300zx turbo. Two sets of rears. They are the same patttern and I run hub rings.

 

I have a 2.7 5spd 4x4 AC and get a little over 22mpg with 265/75-16 LTX-MS2s. I have the lighter P-rated tires instead of the heavier LTs. I dropped a tenth or two of a mpg going from factory 245/75-16.
Don't forget to calculate the wheel diameter difference when calculating mileage.

 

You won't know the damage unless you either correct the speedo/odo to be accurate, or go to the effort of recalculating the actual miles driven every fillup.

But I predict a significant drop. 15-20% at least.

On a 2WD is it worth it? Is there a 'need'?

Don't forget that the OE rims are very narrow, and won't properly accept a tire too wide. Not to mention the added bulk/weight will affect acceleration, braking, ride quality and handling. Un-sprung weight is the enemy of all those things.

 

I run 31s with a 3 inch lift... I get 15-17 mpg. I am assuming you are a 2.7 though, seeing you get 23 stock..

 

Funny, I thought of that this AM. Someone posted Mustang wheels fit, so I knew Z wheels would, as I was a 3x Z owner.

But the TT wheels were wider in the rear, where the NA cars had the same size all around..........

So are you running the same size tires on different width wheels?

Regardless, I'd love to see a picture of them on your truck. I had mine polished. A lot of work on a sand cast wheel like that, but they sure perked up the red car..........

 

IF you can find them OP, 265/75R15's are essentially the same size as a 31" but will save you some weight because they're a 4 ply instead of a 6 ply. The problem may be actually finding options in that size, since it's not as popular as it used to be.
Also, I had 31's on my 99 3.4l 4x4 5 speed ext. cab and I averaged around 19. I got it as high as 22mpg once on summer gas feather footing it on back roads, but it was something of a fluke.
Of course, it's apples to oranges since mine was a 4x4 and a 3.4 and yours is a 4x2 and a 2.7

 

I'm getting around 18 with 31's and winter fuel.

 

31's cost me about 1 mpg or so on my 09 4 cylinder prerunner

 

They are two sets of the turbo rears

 

Gotcha. Very cool. Got a shot that shows the whole truck? Looks like its white like mine, so now I'm really curious!

 

Its silver streak mica....

 

Thanks. Very cool. Bet you get lots of questions on 'what wheels are those!

 

You know, you are the first to ask about them.....

 

well I am currently rocking 245-75 R16, which is stock for a 2014 regular cab 4x4 manual. the tire diameter is 30.5 inches. I am currently getting 18-20 mpg all city driving and thats running in 4x4 cause its winter. get about 20+ mpg in 2 wheel drive. so I am assuming you could achieve about the same mpg