I have a Tera Flex 2.5 lift. My tires are 35x 12.5x 17 with the stock rubicon wheels. With stock wheels, I am running Spydertrax 1.5 inch wheel spacers. With the stock wheels you must use a spacer with the larger tire.
I really like your Rubicon X. I also have one an am about to pull the trigger on a AEV lift and new tires. I've been uncertain about which tire size to go with and still maintain my factory rims as I really like the way the look. Would you please share with me what size lift and tires your running on your rig. Thanks.