I need to know how to save fuel after buying oversize tires?

You will have to go back to stock size tires if you want better gas mileage.

you could change the gear ratio in the rear diff
if you have 4×4 front diff will have to be changed as well
will probly run close to the price of the wheels {got to pay the price for being the boss} you should also look at upgrading your brakes

your engine is working harder to turn the tires hence more fuel. laws of common sense.

Dont drive it. Just let it set in the drive and look good.

If the tires are the same circumference as your old ones, mileage should be close. If the tire is a larger circumference than stock, your odometer and speedometer will register more slowly. If this is the case, your mileage may actually be slightly better due to effectively higher gearing, but appear worse numerically.

If the tires are a smaller circumference, your speedo and odo will read fast and your mileage most likely will be lower. If this is the case, you should have been more judicious in your tire/wheel selection.

Since the tires caused the problem the cure would be to…

You have to decide what your priorities are: Gas mileage or superficial materialism.

To Answer Your question:

1. Get High Gears
2. Get a better air Intake
3. Get an Air Exaust
4. Lower the Tailgate when at highway(aerodynamics)
5. Change your Driving Habbits
http://fueleconomy.gov/feg/driveHabits.shtml

Tho with all those upgrades you might get 5MPG more,
in reality you’ll be saving trips to the gas station but as far as saving money, by the time the upgrades pay off themselvs by saving you on fuel, you might want something elce/new 1-2 ..maibe even 3 years??

I’m getting a 08 Wrangler with 35″ tires, ill be feeling the pain at 14 MPG, but i’d rather give money to U.S. Manufacturers in parts than to the oil industry…untill they start being reasonable with gas prices.

and People, if you offer other “solutions” other than answering the question, dont bother.