TomG, I respectfully disagree with the idea that no one is going to be persuaded, one way or the other. I do agree that there is no way (in the absence of valid statistics) that we can conclude that one type of tire is superior to the other. But there are a few of us reading this thread (I am the OP) who are genuinely interested in informed comments about the reasoning that stands behind the behavior of the tire manufacturers.
A few folks with inside information (like Capri, for example) have shed new light on the topic. My own experience with attorneys representing US corporations led me to believe that the tire companies are trying to avoid product liability and thus recommend ST tires. But I have since learned that the trailer manufacturers are probably responsible for the demand for ST tires and that the tire manufacturers are just responding to that demand.
Which, of course, pushes back the inquiry a step. Why do trailer manufacturers recommend ST tires? Are there government regulations that require them to do so? Or government standards that recommend that they do so? Requirements and recommendations are technically not the same thing, but they are very similar, for all practical purposes. If a manufacturer were to ignore a federal recommendation, that refusal to comply with the standard would be admissible in a product defect suit.
You can see where this is going -- where do those government standards come from? From the regulated industries, of course. They hire lobbyists to shepherd the draft regulations through the administrative process.
Bottom line -- I still don't know the answer to my question. But it is worth thinking about, since there is so much riding on those tires (literally).
