Well the hub centric spacers we are using are pretty safe. My knuckle clearance on my first set of tires you could barely fit a piece of paper between that an the tire but like I said if it clears it clears no matter how small the gap is. 17" wheels might be worth the investment just to save money on tires from now on then you could also get the proper back space so you don't have to worry about that knuckle anymore as well. I know your's isn't a trail rig but the wider stance we get from spacers or new wheels is well worth it on road as well. My jeep felt so much more stable on the road I would never think about going back to stock width again.