89___XJ

Pics welcome....getting 20mpg combined now... stock.
89xj4x4

dogger15

depends how heavy your foot is and what tire you running before you put that size on

highwater

I'm running some 31 x 15's mudders and I I get pretty good mileage still. Like he said above me depends in your heavy foot

1996XJSport

If you're running stock gearing, the 31s will mess up your AW4's shift points. I used to be able to have it shift around 1900 RPM, now it shifts at 2300-2500 RPM. The shifting will kill a couple MPG's because I went from 16 city to 14 city.

highwater

Yeah that's true. My 89 is a stick so not as bad

1996XJSport

Guess who's jealous? This guy right here lol
I really wish I had the AX15 instead of the AW4, so much more control.

highwater

Lol yeah I love my 5 spd so much more control ,lot of coasting on the roads ,but sometimes I wish I had auto when wheelin rocks ,but not many of those here ,she does real well in the mud I have never got stuck and I'm still sitting with no lift so I'm happy with her cause I've put her thru some hell

98cherokeeguy

I'm runing 31s on stock suspension but not for much longer haha they rub very little for me and no trimming was required

dogger15

you also gotta think with bigger tire your spedo will be off along with your odo unless you get them reset with the bigger tires. i know my mileage is off before i has only 215 tires on and now i have 30" tires still figuring out my mileage since it is off but having a 5 speed does help out i love mine

1996XJSport

I'd love to be able to control coasting in my Jeep. I could probably get another MPG just by doing that. The only drawback with a 5 speed is rush hour traffic lol

Biceps McRipped

215 refers to the width of a tire in millimeters, not height. The next number, probably 70 or 75, determines the height. Second number IS NOT the height. Next number is rim size. You're correct on the 30 inch tall tire. Metric tire sizing is annoying.

My jeep is lifted 3 inches with 31 x 10.5 tires and I lost 2-3 mpg from stock. I was riding on 225/75 tires. Both 15" rims.

Width is the key to your mpg. A wider tire is going to create more resistance because of the amount of contact with the road, meaning less mpg. I'm not saying a taller tire won't hurt your mpg, just that a wider tire will hurt it more.

250kcherokee

Im running 31x10.5 and getting about 10-13mpg.

highwater

Yes rush hour sucks I get so mad sometimes

1996XJSport

I get that kind of mileage in the winter with 31s

Metmknice

30s should be alright. 31's I wold recommend finding a 4cyl xj with 4.10s and swap axles.