Gas milage concerns?

What kind of GPM decrease can i expect going from a 16 inch rim with 245's at an avg of 21-23 mpg's to a 18x9 inch rim with 285/60/18's? oh yeah and with a 2 inch leveling kit, if it matters.

 

Be prepared to loose 2-3 mpgs

 

Depending on how heavy your foot is and the type of driving you do, I'd suspect you drop to just below 20 mpg give or take. There's a lot of other factors though, tire weight (load range), wheel weight, tread pattern (All terrain vs mud terrain, etc), climate (location), etc.

 

im going with the terra Grapplers so they aren't to agressive. Yeah I know my foot has a lot to do with it and it all depends on how late im running!