Fuel mileage going from stock wheels/tires to larger tires

[1997XLTRollover]

When I went from 30 to 32 inch tires my mileage barely went down. At the time 5.0L not much lift, awd, I squeezed 375miles out of a tank on the highway

What kind of tread were the tires?

 

[Flash]

Interesting. I guess these 5.0 trucks don't take well to larger tires. As much as it sucks it makes me feel better that there probably isn't something drastically wrong with my rig.

What's your major concern, highway or urban driving?

Both I suppose.

The thing to look at is what RPM your engine is at when you're driving, lower RPM usually means better but not always.
You don't want to move out of the RPM where your engine is producing good torque, your engine will have a sweet spot somewhere.

 

[rabbit91]

What kind of tread were the tires?

BFG ats

 

[1997XLTRollover]

What's your major concern, highway or urban driving?

Both I suppose.

The thing to look at is what RPM your engine is at when you're driving, lower RPM usually means better but not always.
You don't want to move out of the RPM where your engine is producing good torque, your engine will have a sweet spot somewhere.

Where I live it's both. 70 to 75 I'm at 2000 or so I think. Honestly I think I'm lugging it a bit. Plus the torque monster headers probably move the power band up a hair.

 

[TheYeti]

My Explorer is a 98 Sport 4.0 SOHC. I run 32x11.50x15 Mud Claws aired up to 32psi. It has the factory 4.10 gears.

best mileage I've ever gotten was 14mpg all highway on a trip to Ohio from PA. that was hand calculated.

 

[96ex5.0]

I get around 18 - 21 my setup in sig and speedo is set correct. But mine is all gear drive no auto trans with hydraulic s to make it go and I'm set up for getting tq down not HP.

 

[Sonny1597]

I had alot of trouble with mileage and power when I went from the stock 255/70 16" to 265/75 16". Most of the problem was just figuring out the difference in mileage because your speedo is way off due to the change. Figure out the difference in circumference and that will change your mileage.
I have a 2001 Sport 2dr with the 4.0 v6 .. I alway got 18mpg to 22 mpg .. with the bigger tires that dropped .. but not that much when you figure in the error. If I go 200 miles I have to multiple by .0678 to get the correct mileage. So I have actually gone 213.5 miles instead of 200! Makes a difference. I've done this over a couple of long trips with two GPS's to fine tune the accuracy.
You also loose power because you have effectively changed the rear end ratio with bigger tires so not as much power and you have to put your foot into it more to get the same results ... less gas mileage.
I could get 285/75 16" under my rig but to do so I would need to re-gear to 4.11 or 4.56. THat's how I have it figured.
I now get on average about 18mpg .. about 1 mpg less with the bigger tires.

 

[1997XLTRollover]

I had alot of trouble with mileage and power when I went from the stock 255/70 16" to 265/75 16". Most of the problem was just figuring out the difference in mileage because your speedo is way off due to the change. Figure out the difference in circumference and that will change your mileage.
I have a 2001 Sport 2dr with the 4.0 v6 .. I alway got 18mpg to 22 mpg .. with the bigger tires that dropped .. but not that much when you figure in the error. If I go 200 miles I have to multiple by .0678 to get the correct mileage. So I have actually gone 213.5 miles instead of 200! Makes a difference. I've done this over a couple of long trips with two GPS's to fine tune the accuracy.
You also loose power because you have effectively changed the rear end ratio with bigger tires so not as much power and you have to put your foot into it more to get the same results ... less gas mileage.
I could get 285/75 16" under my rig but to do so I would need to re-gear to 4.11 or 4.56. THat's how I have it figured.
I now get on average about 18mpg .. about 1 mpg less with the bigger tires.

I have figured in my speedo error. I get literally 200 miles to a tank max. It was to the point that at 200 miles I parked on a small incline and my truck wouldn't start until I rolled it onto a flat surface.

 

[Spoon91]

I'm running 285/75/16's on '97 5.0L with the stock 3.73 gear for about 3 years now and she does just fine. She's getting about 15ish MPG. Not TO bad I guess.

 

[beach]

I find it funny how my friends 4dr Raptor that's modded, and is just a far heavier truck with much heavier unsprung weight with the wheels/tires and far more powerful/faster.... get's about what I do I on 31s in a 2wd 5.0 lol. Tech advances ftw

 

[1997XLTRollover]

I find it funny how my friends 4dr Raptor that's modded, and is just a far heavier truck with much heavier unsprung weight with the wheels/tires and far more powerful/faster.... get's about what I do I on 31s in a 2wd 5.0 lol. Tech advances ftw

My f150 is the same. I can tow a 7k lb trailer and get better mpg than my ex. Same size tires.