Don't kid yourself, junk off-shore tires are the cause of the great majority of trailer tire failures.
For years I used Carlisle Bias-ply tires on my old TT and thought all this talk about bad tires was probably caused by the operators.
Then I got my first set of Radials and found out the truth. Even with doing everything right (weight, pressure, speed), I had all kinds of failures with those new Carlisel radials - one had a tread seperation just LAYING IN THE BACK OF MY TRUCK under the canopy! Of that first set of five, all failed one way or another. The next set saw a couple more fail.
Then I started using a better tire (Maxxis) and the failures ended.