I like my current tires and was thinking, if I put a 2-3" lift on, would it kill my current mpg. Is it the 35+ tires or the lift?

 

Im an not 100% sure of this as i'm not trueley a mechanical person. But from what i have read and what i understand it isn't really the lift that ruins your gas mpg. I think it is the bigger tires that do this as it takes more power to turn this tires. This i think can be helped out by gearing i think. However did you really buy a jeep to get good mpg or did you buy a jeep to have fun and explore the outdoors.

 

It's not the just the tires.... the higher a vehicle is from the ground, the more air that travels underneath it, the underside of a jeep is anything but smooth, so you're dragging more parts through the air.

 

Lift will have some affect on mpg. Change in airflow. Tires will have the most affect though.

 

I tend to agree with this. Your also exposing more I your axles, so their is an increase in drag there.

Also your driveline angles (driveshafts) are changing. While its minimal, the increase movement in the u joints will create more resistance.

That being said, it's minimal compared to the effect of tires.

 

Weight of stock Goodyear SRA is about 35-36 lbs.
Weight of 285/70/17 or 33's, in an All terrain like BFG AT's or like the Wardens I have is around 58-65lbs. BFG is at the low range, my wardens are at the high range.

Tires only, stock wheels, dropped my MPG by about 2mpg. The tires added almost 1.5" of "lift" to the Jeep, which has some affect. But the weight of the tire is huge along with the tread pattern (more resistance etc.)

I get about 30 miles less per tank of gas with my tires.

 

Surprisingly, mine was the opposite. After adding a 2.5" coil with 35's I actually gained mpg.. I know it's weird, but it rocks!!

 

Its mostly the tires but any time you do a level kit (or lift kit because they level as well) you are going to loose rake (the angle your jeep stock sits slightly leaning to the front). Less rake=less arrow dynamic=less gas mileage. But then again, its already terrible mileage, whats a few less miles per gallon.

 

Mathematically, nothing will be affected by the lift below 50-60 mph. The induced drag isn't enough to change mpg's at low speeds. The size of the tires is what will affect your mileage. Larger tires essentially have the effect of regearing your ride.

 

Its all about the areodynamics, weight, and amount of tire on the ground