I have a 2012 JK Sport that I have installed "takeoff" 18/59 Rubi springs and shocks, 1" Terraflex spacer up front, pro comp 7069 9x17 wheels on. I am running 373 gears and it is an automatic.
My question is will I see a drastic drop in fuel mileage from installing the 295/70/17's on it over the mileage I am getting now with 265/70/17's Terra's?

Will the Procal module allow me to change my shift points to help regain some of my mileage loss with the 295's? Or does it even work that way?

DD Jeep with occasional off-road use on relatively flat Florida swamplands while huntingIf any of you have experience with this setup PLEASE give many any and all your advice you can before I pull the trigger and regret it it. Thanks!.

 

I live in the same area with the same conditions and 3.73 gears. It should not be a drastic hit for that little increase in size. If I'm not mistaken the procal doesn't change shift points. It will just put them back where they should be because of the proper speed being read after tire size correction.

 

You should lose 1-2 mpg, depending on how hard you hit the gas from a start. The procal just like the flashcal, will allow to correct the tire diameter in your computer and therefore the tranny shift points.

 

Do you think I will be ok with the clearance since I gained 2.5" (including the 1" terra spacer) up front) and 1.5 in the rear from the rubi springs and shocks plus I also have deleted my spare and have a license plate Solution Plate on the rear so I removed 55 lbs from the rear.

My brain says go 285/70 but both my tire choices Nitto Terra and Toyo AT II are E rated in that range but I would like to use the wider 295/70 which in the Terra is a D range tire. If I run the wider 295 at 30psi or so wont I equal the slightly shorter height of the stiffer E rated 285's at a similar tire pressure anyway????

Does anyone have 295/70/17's that they have measured at 30 or so psi?

 

The tires will rub at full stuff. While the Jeep is sitting taller now with the stiffer coils and spacer you haven't changed the amount up travel of the axle.

 

On the mpg . I run the nitto terra 295/75-18 and only lost 4 mpg but gained back 2 with the flashpaq and catback exhaust . I aslo have done the 18/59 takeoff swap, but the only difference is I have the ready lift leveling kit 3 in front 2 in the rear. And my jku is an '08. I have no issues with rubbing or anything

 

Since you live in a very flat part of the country, your mpg impact will be minimal.

Saw a big impact on bigger tires when I went from the costal Carolinas to Northern Virginia.

 

I chose 285/70, because I wanted the less impact on power, given that I do not plan to regear. My 10A came from the factory with a 1/2 lift, so I only installed Teraflex 1 inch front and 1/2 inch rear spacers. Again, I wanted the less impact possible on the whole suspension geometry. I chose to keep the stock 10a wheels cause I liked that it looks like a 10a, but had to use 1 inch wheel spacers to regain rubbing free full turning radius. Looks broader shouldered and just right to me. [emoji41]

 

I forgot to mention that I also installed the 2" TerraFlex bumpstop exetenders front and rear, with that bein said I should be ok on axle travel right?

And the rubi coils were 5/8" inch taller than my stock coils right outta the gate. That was with both sets of coils having about the same amount of time on em............both sets had bout 2000 miles on em.

 

4 MPG? what gear ratio do you have? I am runnin 373's...................you runnin 321's?