Why does my 04 ford sport trac get bad mpg? the only thing that is not stock is the tires.?

Question

they're 245/75/16 the org was 235/70/16 is that too much of an increase or is there something else. use to get 22mpg now lucky to get 17 to 18mpg.

Answer 1

you need to get your speedometer recalibrated becuase it is off atleast 5% your current tires and about 1.5 inches taller than your stock tires.

Answer 2

Maybe it is getting the same, did you apply a mileage correction? if not check your speedometer witha GPS unit to find your correction, big tires will slow done your speedo and miles. You should add 5-10 %  to the miles before dividing by the gallons..