Struggling with interstate mileage in 2000 Jeep Wrangler with oversized tires.

[ATaylorRacing]

As far as the width of your tire, a 10.5 is only a tenth wider than the 265 you stated that came on it stock, however....a 205 width tires at 8.1 is 2.4 inches narrower and more CD friendly.

Another factor is the wt of that 31. The first 5 tires in that size from my suppliers come in at an average of 41.6 lbs each....the 265 size tire average wt is 38.2 lbs....not much difference, but some improvement can be had going back to that tire. I am still concerned that that tire did not come on it.

[bestclimb]

have you accounted for the larger tires in your speed and distance traveled? Your speedometer is really counting revolutions of the output shaft on the transfer case. If you change any of the ratios after that point it will skew your speedometer and odometer. Larger tires means your rig will go farther per revolution of the tire making your mileage not quite as bad.

[jamesqf]

Originally Posted by Frank Lee

Where's the fun in that?

If you need to ask, you've obviously never driven say a Honda CRX or Mazda Miata - or even an old VW Bug :-)

[DonR]

Double check your door for the OE tire size. Those would be large OE tires for a 4cyl. I would guess in the range of 205 or 215's were what came on it.

The 4cyl. does require quite a bit of gearing to make anything happen. I would check the rear end ratio to see how bad it is. Your Dana 30 up front will go to 4.88.

I would be tickled pink if my Jeep got 20mpg

Happy Jeepin.

Don

[Abboq]

Originally Posted by ATaylorRacing

Jeep SE
225/60/16 26.6" 60=69.9 16.5% off
205/75/15 27.1" 60=66.6 14.3% off
225/75/15 28.3" 60=65.7 9.5% off

Those tires sizes seem a lot more reasonable for a stock four-cylinder. I have probably about 20,000 miles of tread left in the current tires, but the acceleration and mileage is so poor, I may consider an early switch.

I've found a few 4-ply (standard load) 15 inch tires that are only seven inches wide and are each about 10-15 pounds lighter than the average 31x10.5 load range C tires I've looked at. I also have a full sized spare, so that could cut 10 pounds of sprung weight and 10 pounds of unsprung.

Don't narrower tires usually work better in shallow mud and snow anyway?

[Abboq]

Originally Posted by DonR

Double check your door for the OE tire size. Those would be large OE tires for a 4cyl. I would guess in the range of 205 or 215's were what came on it.

The 4cyl. does require quite a bit of gearing to make anything happen. I would check the rear end ratio to see how bad it is. Your Dana 30 up front will go to 4.88.

I would be tickled pink if my Jeep got 20mpg

Happy Jeepin.

Don

I believe my model came with either 3.56 or 4.10. I've been reading on 4bangerjeep that a lot of guys running 31s end up really happy going with 4.88s.

[Abboq]

Originally Posted by Wonderboy

Do you need a jeep? This is a serious question... just making sure. If you need it, it may be worth considering buying an inexpensive little car with twice the MPG that you use for regular highway commuting and such and just use the jeep for what you actually need it for.

I must confess I don't really need a Jeep. Strictly speaking, I don't need to drive at all. I originally thought that a Jeep would work well for where I live. Last year, my two-wheel drive pickup and I got stuck four times (twice a friend's 4x4 pulled me out; twice I had a tow).

I had considered a 4x4 pickup for myself, but I didn't want to continue getting 14mpg. Even the little Rangers and Toyota 4x4s seem to be pretty hard on gas. And I don't want to mess with the new automatic locking hubs.

I was hoping I could get a 4 cylinder Jeep and get in the early twenties for mileage, and still have 4wd available when I struggle. I'm getting way better gas mileage than my 1995 Dodge Ram 1500 with that 5.9 liter V8. It got 14-15, no matter what I did to it, and I tried about everything.

I do plan to keep this Jeep running forever, and I've read they'll do it if taken care of. I know that a significant percentage of a vehicle's overall energy price is used just to create it.

I am honestly considering buying a cheap, second used car that gets in the high thirties for when it's dry out.

[Frank Lee]

Just about anything will run forever if you take care of it.

[MadisonMPG]

So you need one because you don't want to get stuck? Reasonable reason for keeping it. (take note all of you in your lifted highway queens) It has been mentioned, and i'm usually the one advocating it... buy a car.

Oh, BTW, you don't have to thank every post that is decent.

[brucepick]

Originally Posted by Abboq

I must confess I don't really need a Jeep. Strictly speaking, I don't need to drive at all. I originally thought that a Jeep would work well for where I live. Last year, my two-wheel drive pickup and I got stuck four times (twice a friend's 4x4 pulled me out; twice I had a tow)....

Do you have snow and ice, or other issues that might make a Jeep a good choice? I deal with snow regularly in New England - and I'd pick a fwd car with four snow tires over a fuel-sucking 4x4.

If you're dealing with mud or other hazards, do tell.