That's an awful can of worms. A lot of the ST trailer tires come from Chingchang manufacturing and depending on which door they come from and level of quality I think it's still a crab shoot. I use one load range higher than requirement on my boat trailer, ST 5.30x12 LR"C", they have a higher capacity. On my cargo trailer I use the radial 205/75/15R. Knock wood, I keep an eye on the cold tire pressure and so far no blow outs. I had tread separation on a boat trailer tire one winter, a big goose egg between the tread and carcass. Regardless of mileage, I swap the tires out every 5-6 years unless the tread is worn down earlier. Avoiding potholes, etc, is big on my list. You see people driving with complete oblivion as to their road surface surroundings, pay attention, it pays in the long run.