[mbrooks9]

Before I start, I know we don't buy trucks like these for fuel mileage or economical driving. My concern is with the dramatic change. I want to know if something is wrong, or if I caused the change.

I just leveled the truck and put an aggressive 35x12.50x20 on it, which I know didn't help. I went from averaging 16-17 on a 265/70/17 to only 11 or 12 mpg. If that normal?? How much will deletes help?

 

[MSchroeder]

speedometer is off so you are going faster than indicated and your odometer is off as well, larger tires travel further per revolution than before showing less miles traveled than actual. both effect the fuel economy calculations in a negative way.

 

[Wandell]

Yep, you went from a tire approximately 32 inches tall to one almost 35 inches tall so your speedometer/odometer is off. No doubt the small lift and taller tires had a negative impact on you MPG's but you will not know how much until you correct your speedometer/odometer.

 

[mbrooks9]

Gotcha, makes total sense. I just didn't figure that it would amount to so much of a difference.