I just installed new 285/70/17 tires on my 2008 JKU X model. The stock tires finally had enough wear to justify replacement and damn it looks sooo much better! Do I need to reprogram anything to keep my speedo and odometer correct? I know this is not a big size change from stock, but I want to make sure my speedo is correct. What are the best ways to accomplish this task? I may spring for a programmer eventually but that is not in the plans right now. Thanks!

 

I'm pretty sure you will. AEV Procal will do it.

 

I just put 285/70r17's on my Rubicon. I have the navigation system. With the stock KM's, my speedometer read 1mph slow at freeway speeds compared to the navigation system. It is now right on. I assume you don't have navigation, so check it with a GPS and see if it's actually off.

 

The dealership can set for stock tire sizes. Some people have posted that their dealership did it for free, others are charging up to $80 or so. Again, stock tire sizes. (ex - going from stock 29's to take-off 32's from a rubi or sahara).

Once you go taller, the ONLY option is an aftermarket programmer or tuner. The aev procal is the cheapest option. Great features for the price. Beyond that, you are looking at tuners that are a few hundred more.