Gas mileage.

[FExplorerL]

1993 Explorer 4X4 and I am getting 14mpg with 255/65R16 tires. Is this normal? Also running at too low rpm can give you bad gas mileage how? I ask because I usually cruise at 1500 - 1600rpm @ 80km/h.

EDIT: With 3.27 gears.

 

[MrQ]

1993 Explorer 4X4 and I am getting 14mpg with 255/65R16 tires. Is this normal? Also running at too low rpm can give you bad gas mileage how? I ask because I usually cruise at 1500 - 1600rpm @ 80km/h.

EDIT: With 3.27 gears.

Two points here;

1) Your tires are WAY to large for that gear ratio. 235/75/15 are the correct tire size.
2) Lower rpms are always better for gas mileage, because it takes less fuel to maintain the speed.

 

[FExplorerL]

What would go wrong if the tires are too big for the gear ratio?

 

[MrQ]

It puts more stress on the axleshafts, gears, driveshaft, and transmission. The engine also has to use more gas to get up to speed and to maintain that speed.

 

[red.EDDIE.4x4]

before the lift i got about 16 to 17. now i get 13 at best with 33s