Some 30+ years ago, I was engineering manager for a large fleet of oil field service trucks, mainly 18-wheelers and heavily loaded with pumping equipment. At least at that time, tires were designed to have the treads re-cut once, then after that wore down, the tire bodies re-treaded. We had a company in, as I remember, the Dallas area which did all our retreading and they were very good about inspecting and rejecting tire bodies which were suspect before retreading. We never had any problems with treads coming off, but we had very strict requirements about our drivers inspecting their vehicles before leaving for every job, including maintaining proper tire pressures and inspecting tire condition. These were not long-distance runs, typically 100-200 miles per job or less, so the tires got inspected almost daily.