We had the same problem, 2 trips 2 blowouts and damage to the wheel skirt, underbody trim and wheel well. We could not figure out why. When we looked at the tires they were in good shape with lots of tread left. We then looked at the weight load, and found the problem. We are ok for a empty trailer, but when we loaded with everything they did not meet the GVW. We are about 7600lbs(GVW), the tires on the camper were rated for about 7000lbs. We purchase all new rims and tires(Carlisle) we went to 2150 and D rating even though the trailer says C. We have not had a problem since. The test was about 2 weeks after we drove 9.5 hours in 100 degree weather at highway speeds and not a issue. We learned a new respect for what they go through and the first thing we will check on our next new trailer is the tires first and then the GWV and make sure the proper tires are on the unit. Good luck!
Sheldon & Kathi Hartwell
Dexter and Ryley our beagles
2003 Forest River Flaggstaff 829 BHSS
2001 Lincoln Navigator All Wheel drive