I'll keep this as short as possible. Let me start by stating that I never exceed 60 mph, always check the tire pressure and keep it at the 75 PSI, and all the tires were less that 4 years old. I am reasonably sure that I am not overloading the tires. I keep the heavier stuff in the tow vehicle and in a cargo pod on the tow vehicle. Took my family on a 3,380 mile trip down to Corpus Christi, Texas and back through six different states. We started out by spending two nights at a hotel in Dubuque, Ia for my Aunt and Uncle's 50th wedding anniversary. About an hour out from Dubuque on the third day a passing car waved us down and told us our tire was going flat. We pulled off into a parking lot and found that the tread on the driver side tire had separated all the way around the tire. The tire was still fully inflated. This was a Carlisle USA Trail. I put the spare tire, another USA Trail, on and we continued on our way. The next day we found a tire shop near Lawrence Kansas and had them mount a new tire on the rim. It was a Nanco tire. The rest of our trip went just fine all the way to Corpus Christi, Crater of Diamonds, and then Meramec State Park near St. Louis. We left Meramec to head over to Cahokia Mounds and then home. We were on the road for about 45 miles when there was a really loud bang and pieces of tire flying everywhere. I pulled off the highway and into the parking lot of the Route 66 State Park. The people there were really helpful. We put the new Nanco tire on. I checked the pressure and it was only 55 PSI. The sate park had a garage right there and they let me use their compressor to pump the tire up to 75 PSI. We got back on the interstate and were trying to decide whether to head straight home or still stop at Cahokia when I felt a vibration. I looked in the mirror and saw the trailer start bouncing and then the tire went flat. Before I could get over to the shoulder the tire had wrapped around the axle and locked the rim. The rim started grinding on the pavement throwing sparks. The BRAND NEW spare tire had lasted 3.5 miles. I pulled as far off the shoulder as I could and we called AAA because I wasn't going to make it to the next exit with the rim grinding away. The AAA people were really helpful as well, making several calls to try and locate a new tire and rim. No one had the correct rim and only one place had a tire. We wound up going to a U-Haul place to get a cargo trailer to bring the contents of the pop-up home until I could get new tires and go back for it. At the U-Haul place, I found that the new Nanco spare had been mounted using an inner-tube even though it is a tubeless tire on a tubeless rim. Looking at what is left of the inner tube it is obvious that that the valve stem is designed to stick straight up through the rim, just like on a bicycle or motorcycle rim, not at the the angle that the valve stem hole is on a trailer rim. I am pretty sure that as soon as we got moving and the tire started flexing, the inner tube shifted and that caused the rim to cut into the valve stem. As far as I can tell from this site and others, putting an inner tube in a tubeless tire is not a good idea. What do you think? I have some pictures I can post as soon as I get them onto Flickr.