by 1955 tubeless were standard equipment on new vehicles and AFAIK the truck rims didn't change then, although some tire shops seem to think radials won't work on them .... I've always put tubeless radials on the old trucks as long as the rivets weren't corroded and never had a tire shop object .... LONGBOX, I think the rim that "locks" the bead is called a safety wheel and didn't start until about the 70s, strictly for a "run flat" precaution - as you say, keep inflation checked and correct
Bill
