SEVERE TIRE WEAR- followed by tire blowout at 55mph

You may have trouble getting either Dexter or Jayco to replace anything but the original, but you're going to continue to have trouble at 2200 lb. You need to get 3500 lb. on there--maybe you could talk them or the RV dealer into letting you pay the difference. Our first trailer had almost the identical dry weight as yours, but came with 3500 lb axles, and we ended up breaking a spring on ROUGH I-86. Even if you have 3500 lb. springs, they will not be too stiff with the weight that you are carrying.