50 mm wider (2")
You will need spacers with stock 18's
Besides, if you are rubbing now, what would happen when you add another inch on the backside.
Not to mention if you ever disconnect it will be an obvious issue.
For about $100 you can get a set of 4 spacers.
Black Forest Green 2012 JKU Sahara, Tinted Windows, Chromed Door Handles, Star Fab Door Stops, Brake controller, Poly Filled Speakers, Black Hole Mod, DIY Grill Inserts, Blinker Mod, Aries Front Bumper, Spyder Rear Bumper, 2" Rancho Lift, Quick Disconnects, 10K Warn Winch, Helix Air Compressor 315/70/17 Duratracs on 17x8.5 Warlords, IL-PU36, X-treme 9008 bulbs & PIAA's