Lee, my coach does not have a tag. It has a 21,000lb. rear axle. My coach completely empty except for full fuel and full fresh water (empty black and gray tanks) weighs 20,280lbs. on rear axle and 10,720lbs. on the front axle, so YES, I need J rated 18 ply tires. That is unless somebody makes a tire of a lesser rating that can haul that amount of weight. Marty