Would I get better or worse gas mileage if I get bigger tires on my Jeep Wrangler?

Question

I have 30x9.5 tires right now. How much better or worse would the gas mileage be if I had 32x10.5 tires?

Answer 1

Unfortunately there is not a yes or no to this. Yes, larger tires do have greater rolling resistance, are harder to start and stop. You acceleration will suffer. ..Bad things..
But you do not want to hear that...Ok..What Wrangler do you have. The offroad versions do have the Dana 44's and so the axles are strong..if not you have Dana 35's..NOT good.
What axle ratio do you have? 3:55 or numerically lower is not good. You engine will be lugging to pull those larger tires. Please tell me you have the 4 liter!! Not the 4 Cylinder.
If you primarily drive fairly constant and around town, you might see better milage, due to a drastic engine rpm reduction, but at highways speeds, unless you have the gears for it. .and it does depend upon you gear ratio, you may see similar, or reduced due to the engine pulling too hard.
Your braking will be reduced due to the weight and diameter,,but in general...it will look cool...Have that size on my 1974 CJ-5...just because others us the 31x10.5's...Oh, yes, are you sure you are getting the 32x10.5 or 32x11.5, which is more common. The narrower would have less interferance and rolling resistance but harder to find.
Do you have limited slip? Consider that you need the larger spare. If you put the smaller tire on only one side of a limited slip axle, you create a LOT of wear and heat quickly.
Good Luck

Answer 2

When you changed the tires did you re-gear it? If not....there is the problem. I have a 1991 Wrangler w/ 2-1/2" OME lift & a 1". This Jan I'll be getting new Tires. They'll be 31s like yourself. I have a 4.0 3 speed auto tran. The stock axle gears are 3.07. To keep my mileage I'll need to upgrade my gears to 3.73, but I want more low end grunt for hills and rocks so I'm opting for 4.10s. Yes the tires make a difference. What year is your Jeep? What motor? Which transmission & how many speeds? Use the links below. Very handy tools.

Answer 3

Well, I am not going to beat the drum because it has been said here many many times. The caveat is that you can have big diameter tires without dinging your gas mileage as much if you are willing to keep narrow tires which tuck neatly under the stock fender wells. BF Goodrich All Terrain TA/KO 33X9.50 15s are an extremely good tire and offer gas mileage very near the levels you have now.

Just remember these tire "wheel" differently offroad than the wide tire and they require more of an "Old School" style similar to running the old CJ3 with the 16" Goodyear Town & Country or Firestone Surburbanite.

Hope this does not make things any more confusing, but you can have your cake and eat it too.

Answer 4

What year is your Jeep and is it a 4cyl or 6cyl? I have a 2000 Sahara (6cyl) with 32x11.50 mud terrain tires on my Jeep (with 1 inch spacers and 3" coil spring suspension lift) and there's not that big of a gas mileage difference (slight difference, nothing to complain about) than when I had the Jeep stocked. (and I have the Dana 30/35 on mine and no problem whatsoever, and I have also been off-roading with no problems). I have to agree with the above though, the bigger tires are harder to stop, so I would suggest getting some good brake pads put on, not the cheap ones. Just remember, the bigger the tires, the heavier they are, which causes more stress on the vehicle, leading to less gas mileage.

http://www.myjeepspace.com/CarolinaShygirl

Answer 5

A bigger contact patch (the surface of the tire that meets the road) the more rolling resistance you'll have. More rolling resistance=lower gas mlage

Answer 6

Taller less rpms wider more rolling resistance. Then you add wind resistance of the tires hanging out past the fenders. Your killing me here! And your gas mileage too. Your stock differentials are not heavy enough for your current tires. So just go larger and break a pinion gear bearing or knock a tooth of the rear ring gear. In 4x4 damage the front differential or break a U-Joint yoke.

Answer 7

The bigger the tire, the more energy it takes to make it spin. Especially knobby tires use more gas.

Answer 8

I hope I'm the winner ... other's answers are right in line. You will get worse mileage. However, you purchased a very cool vehicle and so that it doesn't look funny, you should consider putting 32s on.

If you want to save gas, buy a moped to go back and forth to work -- the money you save will help you afford those new meats. Personal recommendation, Goodyear MTRs. (!)