I have a 2006 Carriage 5th wheel. Fully loaded on a trip at a scale it weighs a fraction over 14,700lbs. Out of that the fraction over and 3100lbs is hitch weight. So I have 11,600lbs on the tires. I have been using the XP Rib for almost the whole time I have had the trailer. I bought it new. It had the Towmax china tires on it from the factory and they lasted for 7000 miles of towing . As soon as one showed signs of going bad I replaced all five with the XP Rib.I am on my 2nd set now. I replace them every 5 years by the date on the side of the tire. I have never had a problem out of them.The side wall also has a steel belt. They are heavy if you try to pick one up.
You did not mention your hitch weight in your 1st post. Is that included in what you posted. If so, you have less weight on the tires