Okay... so tire sizes 101:
XXX/YYrZZ
- XXX = Tire width in millimeters
- YY = Tire sidewall ratio relative to the width of the tire. Said another way... percentage of the tire width that makes up the sidewall. For example, if your tire width is 275mm and your sidewall ratio is 70... then your sidewalls are
275mm * 70% = 192.5mm
- ZZ = Diameter of the wheel in inches.
The stock Outer Banks tires are (255/70r18). Using that you can figure out the diameter of the tire:
(2 * 255mm * 70%) + 18" = 32.06 inches
You can fit up to a 290mm wide, ~33 inch tire on stock Outer Banks suspension without any major modifications. The problem in your case is the stock Outer Banks wheels are 18 inches in diameter and 7.5 inches wide. You aren't going to find a 290mm wide tire that will fit on those wheels. The best you can do is probably going to be ~275mm wide. A 275/70r18 tire will give you look that is somewhere in-between a stock Black Diamond and a stock Badlands. So if you want a beefier look that what the stock Badlands has, your only real option is to go with different wheels and/or a lift.
Here is a reference of all of the
stock wheel/tire sizes in case you need it.