I am new to the forum, I recently purchased a 13 JK. I am thinking about buying new 32in tires, but I am not sure if they will effect the computer in the Jk. The computer in the JK will tell you, your MPG's and miles till empty. If I were to buy new tires, which are larger then the stock, will the computer compensate for the larger tires and make the adjustment? Or will I need to take it into the dealership and have them adjust the computer?

 

Look into an AEV Procal or one of the various tuners. They can make those adjustments for you so you don't have to see the dealer.

 

The dealer can compensate for 32" tires. Or you can get a procal

 

I went from stock 225/75-16 to 265/75-16's and my dealer said they could not program for the tire change and they recommended I get an aev procal. Not sure if they were full of sh*t but I found it funny they recommended the procal. I did get one tho because my speed and odometer were off a bunch.

 

So if I go from 255/70r18 to 275/70r18 I should have any problem either... What do you guys think??

 

You're only going up 1" in size. Not a big enough deal to worry about honestly, but if you plan on getting 35s+ then I'd get the procal or another tuner so your computer can adjust its shift points (if you have an auto). If you have a 6spd, don't worry about it.

 

Thanks for this post reply! I am putting 255 80 17 on my new 13 JKUR and am worried about the speedo, odo, and computer. These are true 33" diameter tires, about 1" taller than OEM 255 75 17.

You are setting my mind at ease. I was about to drop $149.00 for the AEV Procal even though my JKUR is a manual.

 

I've recently gone from 32"s to 33"s and the speedometer isn't really affected much, and the shift points are fine. If you get a larger tire, like a 35" as stated above, definitely get the procal. Otherwise, you can take it to the dealer or just live with it. I honestly don't think you'll notice a difference.

 

Awesome !! Thank you!!

 

If I remember correctly this is around 3% change. That means at 55 you are only off by a little over 1-1/2 mph. Now at 100 you will be off by just over 3mph so be careful of them smokies if you go strictly by speedo when you're cruising at the ton . This is from the Rubi's 255/75-17