Gas mileage problems

What do you have done to your truck

 

Shell, King Suspension, 285 Ko2's, SCS wheels, BAMF Skids, Sliders. Pretty much took a hit with wheels and suspension alone. The 10 ply tires are heavy AF. Probably what is killing it the most. Might get a little bettter with a gearing change.

 

It might be the weight killing your MPG. I don’t know what driving habits you may have or cruising speed on the highway.

When I had by E load 285s with a 3 inch lift I kid you not, I got ~23MPG from Santa Cruz to Pismo Beach crusing at 65 the whole way there.

On the way back home cruising at 65 I got about 19MPG with headwind here and there.
I had no extra weight besides my lovely passenger.

 

MPG took a shot before adding all the weight just lift and tires. On a easy drive best I have been able to get it 14.7 and that was on my way back from Tahoe so there was alot of downhill.

 

I get 19mpg city in winter with 265/70/17 KO2's load range C. 21 highway all the time. Load range E would kill my MPG's, function over form.

 

Wintertime kills your MPGs and it's more than just running winter blend fuel. Combined with what your truck has 11-13 sounds about right.

https://youtu.be/tctTK6bku6o

 

Like everyone else said.... tires/wheels/lift and not correcting for the increased tire diameter. So part is build, part is math.