IMHO, IF those Michelins are really new (read the date stamp) they should be good for 4-5 years. I've seen posts by folks who've had them blowout (Montana forum), but not many. The problem with ST tires is they almost all are rated for only 60 mph, so check the fine print on your tires and don't exceed the rated speed. This is the biggest reason I believe in LT tires on any trailer. They also have more reserve capacity that ST tires don't and are built to take more abuse (think of what trucks go through vs. trailers).