This from tireman9 who is a actual tire engineer and a RV.net member. Don't assume your very short miles/years experience speaks for everyone concerning operating your lightweight trailer with ST tires in excess of the ST mfg max speed ratings.
Tireman9 reply in the Heartland tire forum
When people run a tire overloaded or underinflated or at excessive speed there is damage done to the internal structure of the tire. While tires are made of organic materials they do not repair themselves.
Microscopic cracks just continue to grow. Rubber that has been overheated has permanently lost some of it's flex and elongation capabilities. Maybe the best way to think of this that tires have a finite number of "life cycles" Each revolution consumes some of that life.
When overloaded or underinflated those cycles consume more life than cycles run with more inflation or less load. When run at a hotter temperature each cycle consumes more life than a cycle when the tire is cool. Certainly the faster you run the higher the temperature of the tire. With enough speed the temperature can cause the rubber to "revert" or de-vulcanize. If you have ever heard the term "Tire Blister" in relation to a NASCAR race that is what happened. The rubber reverted.
Some folks get 5 years out of their ST type tires while others consider themselves lucky to get only one failure before two years. It is the cumulative damage of high load, low inflation and high heat that determines the actual life of a tire.
Just as putting the burnt hot dog back in the fridge does not repair it after it was damaged on the grill, slowing down or unloading the RV or increasing the inflation will not repair the tire.
