I'm getting 315/70/17 dune grapplers and have 3.73 auto 08 jk. It's a daily driver and the beach is the only off road. I would like to have anyone chime in on gas mileage, performance, ride, etc. good or bad all welcome. Engine mods are k&n intake, exhaust, superchip on 93 octane setting. Let the ideas fly!

 

My opinion is you'll have some trouble, gas will drop some depending on how much weight you add to the body with heavy add ons. Performance would drop because you have an auto trans. With that size tire and gear ratio on an auto it'll be tough, regardless of your intake and exhaust, it might still might be bearable for you since you said you don't offroad much. You're main problem is just your auto trans...

I have 315/70R17 Nitto Trail Grapplers on my '08 JKU with a manual trans and cat back exhaust with CAI, no programmer and the stock gears worked well enough for me on the highway, OK offroad, but got worse when I added to bumpers and stuff to it. You're going to experience more torque loss than I did with the auto tho...

 

I have a 08 jku with 373 auto hard top. I am running toyo mt 285/75/17- 97lb ea with teraflex 3.5 lift front bumper and vr 10000 wench a kn drop in filter hypertech programmer on 87 octane 17mpg.almost 107k.

 

And? What's the verdict?

 

Do you think it's doable to run 285's for a while before getting a lift?

I have a sport s with factory 255/75/17's

Matthew

 

I have 315 75 17s and 2.5 inch lift with 410 gears auto trans. With programmer intake exhaust. Front Psc brawler lite and its bearable for me.