I looked that tire up on their web site. There are 2 different load range tires in that type. Hopefully you had the heavier load range. Even that looks to be a fairly light duty tire for what you are doing with it. What is the weight on the rear axle. If it is much more than 60% of the tire rating you will have problems. That's why most of the bigger rigs went to 22.5 truck tires. Motor homes exert a lot of force on the rear tires due to the long overhang in the rear. You might want to look at a heavier duty tire.