mpg loss with 1 inch wider tires?

Every time I calculate my MPG it just comes out to "BAD". What am I doing wrong?

 

I hate that damn MPG display. I doubt it's giving anyone a close to perfect read, and just fucks with you every time you make a change to your truck.

I can fill up and drive to my folks winter place which is 254 mile round trip, and burn just under a half tank...according to the gas gauge, which we all know isn't perfect. It would be the tits to get 500 miles to a tank!

When I bought my 4.0 Jeep and filled it up, I drove about 25 miles and it was on 3/4 tank. I thought to myself "self" this is gonna suck, but found out the gauge would go from full to half a tank super fast, then it would take forever to get from half to near empty.

 

I thought so too, got them for $400 from some gentleman on here

 

On the 2010 Tacoma I used to have I went from stock 245/75/16 to heaver 245/75/16 with a full size 1/2 ton truck weight rating and I saw a 1 mpg drop in gas mileage.