Kinda a weird question, but can you save fuel money by increasing your tire size?

Kind of – yes.

That has the effect of lowering your cruise RPM. But if you end up hitting the gas harder to compensate for lower HP, then you might undo any upgrade.

Also your speed will be off.
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It has been shown that changing driving habit actually does the most to increase the gas mileage (even more than having the proper air pressure, air filter, etc.). Whenever you can use your cruise control.

Good Luck

No. You will actually lose gas mileage because your engine is pushing bigger tires.

Technically your odometer will clock less miles than you drive so it will throw the calculations off a bit. Your best bet is to add a little extra air to the tires, its easier and cheaper.

your car was engineered to run most efficiently with the size tires it was built with. to save fuel make sure you keep them properly inflated, avoid “jackrabbit” starts and believe it or not the”takes 3 miles to reach the speed limit starts” waste gas as well. use cruise controll to maintain constant speed when practical, the computer in your car that controls “cruise function” does a much more accurate job of balancing engine rpm, vehicle speed, and trans shifts than your quivering foot can. and shop around a little for the cheapest gas in town,,, it all burns the same plus do regular maintenance,, nothing waste gas worse than an ill running eng