I have only owned my enclosed car trailer (24" Wells Cargo "Auto Wagon") for 4 years, so I don`t have lots of experiance with trailers at this point. My trailer has full aluminum checkerplate floor, upper & lower cabinets and work bench,awning, left side door etc, and with the car, tools, generator, compressor, fuel, water, and all the other stuff that typically goes into the trailer, my trailer is normally between 8500-9000 pounds. My trailer has 5200 pound torsion arm axles, which allows for a lower floor height than leaf springs, and supposedly a much smoother ride. These axles use 6 stud 15 " wheels, with ST 225/75R15 tires. The trailer came new with Goodyear Marathon trailer tires, but by the time I bought the trailer in 2014, it had a set of Chinese Gladiator ST trailer tires, with lots of tread, but were 5 years old.The Gladiators were Load Range E (10 ply rating), and since they looked great, I left them on, and ran them at 75 PSI (sidewall claims 80 PSI max). I normally only put about 2 or 3000 miles a year towing to races, the furthest is about 700 miles, a longer haul, especially in a hot climate is suppossedly much harder on trailer tires. I did have a trailer tire blow out last summer, I didn`t even know until somebody drove up beside me waving their arms and yelling. It was the RF tire, and the leg for the awning blocks the view of the trailer tires on that side. The tire was completely shredded, but luckily did not rip off the fender, or tear the aluminum siding off, although the side of my white trailer did have a lot of black marks from the tire flapping around. This happened about 3 1/2 hours from home, and my spare was the original Goodyear that came with the trailer when new. It had never been used, but was 15 years old, so I drove home pretty slow & carefull. Like Jay said, lots of opinions about trailer tires, some guys said to switch to 16s, and use a 235/85R16 truck tire, others said 15s OK, but use LT tires, others to use the same type tires as factory, and replace them every 5 years. I did look into the 16s, although trailers sold with 16s normally have 8 lug wheels, you can buy 16" wheels with 6 stud, but in my case, the axle spacing and height of the inner fenders, there simply was not enough room for that tall of tire. After doing more research , I chose to buy 4 new 10 ply Maxxis ST trailer tires, and use my original wheels. At the time, I was unaware that trailer tires normally require special high pressure valve stems, when I bought the trailer, it had had regular valve stems installed when the Gladiator tires went on. I also found out that ST tires are speed rated to a max of 65 MPH. When I towed empty up to Kamloops, to pick up my 59 Ford from paint, I was hitting 80 MPH, so that may or may not have contributed to the tire failure. The Maxxis tires seemed to have the best reviews for a ST tire, and DalePs Pace trailer came new with Maxxis, and he used them for 10 years. But Jay.if you are going to order a new trailer, I would seriously consider getting the 16" wheels & tires.
