Why are container trailer wheels and tires different?

The open rim with a removable side is legal; the outlawed rim had the actual rim with a split that would overlap when removing the ring. The rim would wear a the overlap area and were considered bombs...came back from the tire shop with just enough air to lock the rim. They had a nasty reputation of removing tire men's legs just above the armpit.....

In 1972 we traded in 45 tractors at a Chem Leaman cement terminal. The other 'college kid' and I changed out all the drives from those trades with two flatbed loads of 'run offs', tires that Super Tire couldn't cap/section or plug any more...

A lot were mounted on the old style [soon to be outlawed] split rims and had, maybe 15# in them. The over laps were so bad that we would place the inside tire on the hub spokes and standing to the side, use sledgehammers to bump the tire 'home', throw on the spacer and mount the outside and torque up the lugs before we aired 'em up with a clip on air chuck...