Tire rack.com lists all the size tires that will fit any vehicle. P255/50R19 are not listed for the DJ. Dodge used this size tire on the Red Show Crossroad last summer. My Tire Dealer had reservations ordering this size, but I told him that they had to fit because Dodge used them. As I mentioned, I can not get my index fingernail between the lower spring mount on the front struts and the inside of the tire. 50 has to be the widest tire that will fit, at least on a 19. There are a lot more sizes available for 17" wheels, when compared to 19". A P255/50R17 may not fit. If you don't pick one of the sizes recommended, then it becomes trial and error. Usually, you are safe going one size over; sometimes 2, but then you will begin to throw off the speedometer. My tires are 10.04" wide; 1.18" wider than stock. .59" wider on each side. Maybe go by the width of the tire. And, I believe that the Crossroad wheels have a slightly deeper dish, so the tire sit slightly towards the outside of the DJ. A lot to think about.