So I've done some searching on this but I don't have a clear answer... I recently added 305/55/20s to my 09 suburban and I find that it likes to drop to 5th when going up even small hills. This is hard on MPGs. I have 3.42 gears. Has anyone on here upgraded to 33s and then changed over to 3.73s or 4.10s? Did the steeper gears improve mileage any?