I ran 31's on stock rims for a while with no problems, It just looks a little narrow. Stock rims have a little too much backspacing. 3.75" backspacing works well on a 15x8 rim when you decide to upgrade.
2013 Wrangler 2D, 3.6L, Automatic, 3.73 Gears, Limited slip in the rear, Teraflex 2" lift, 285/75/16 tires, LOD bumper & 8K winch, 2M Ham radio.
People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf- George Orwell