My wife and I are packing to move in a month or so. We have a large collection of "family" heirlooms, mostly furniture, art work, glassware and dishware that we needed to offload to other, one generation younger, family members. They came to our place and picked what they wanted, but in most cases didn't have a truck to take the bigger pieces home. Most live 200 miles north, so I volunteered to deliver in my '52 150 flat bed. Bill Brubaker offered the loan of his 5x10 two wheel open trailer. We looked at the receiver on my truck and decided it needed re-engineering. We ended up cutting off the receiver (it was just butt welded to the rear crossmember) and mounting a new one to existing bolt holes along with additional cross bracing. Filled up the back of the truck with a little artwork, a couple boxes of glassware and mostly furniture. The trailer had an 8' couch and a large padded swivel rocker. Checked the tires the day before at 50 psi. I'm not very experienced in trailer operation, so I took it easy for the first 10 miles or so on I-45. Finally got it up to around 60 and felt OK. 10 miles later I noticed that the back of the truck was wagging a bit, accentuated by the trailer. I checked the speedo and I was at 66 MPH. Slowed back to 60 and all was well. 10 miles later it started wagging again. I was back at 65. Slowed back to 60 and all well again. Did my best to maintain 60 in a 65 zone. A few miles later and wagging again, worse than before. I was at 58 MPH. Tapped the brakes and tried to get onto the shoulder. The truck was in the right lane, swerving back and forth from the left lane to the shoulder. As it slowed I was concerned it would jackknife. This is about the time I realized I needed a new pair of shorts. Luckily there was no nearby traffic. Finally got it to the shoulder. The right rear tire on the truck was completely flat. 2 Good Samaritans stopped to help. Changed the tire with no more major difficulty than disconnecting the trailer so there would be enough room to get the under mounted spare off. The rest of the trip was uneventful, with speeds up to 73 MPH downhill. Tires are a set of Specialty Tires of America, LT 7.50x16, bias ply, load range D, 2440 pound max, tube type tires that the previous owner had put on shortly after he bought the truck 6 years ago. They look great and very appropriate for an old truck. The truck had virtually no miles for the first 2 years until I bought it and got it on the road. Since then, maybe 13000 miles and they still have almost 1/2" of tread depth left. Took the tire in for repair if possible. The guy call me back and says the puncture is too large to plug. "Plug?" says I. "Plug" says he. I say "It is a tube type tire." He says "No tube in this one." Question: How weird is it to run tube type tires tubeless??