If you are going to run 8.25 tires on a 6" rim, I would recommend using 7.50 tubes. Otherwise the tube will fold and will develop leaks in the creases in no time. Are the 8.25 radials. If so, you need to run a tube designed for radials. I doubt if 7.50 radial tubes are available. Tubeless truck tires really didn't become common until the late 1970's. I started switching my fleet from tube required to tubeless in the early 70's. My drivers carried an assortment of sheet metal screws because usually we couldn't find anyone to change tubeless tires. The drivers were instructed to pull out the nail and put cement on a sheet metal screw and screw it in the hole. That worked until we could get it patched from the inside. The reason I changed to tubeless was that almost half of our flats were caused by folded tubes and if drivers didn't notice a flat on a driver or trailer, the friction of the tube flopping around would catch fire. Tubeless tires eliminated all this and they are actually much easier to change.
