1999 COBRA SALEM Tires Problems

OCTOBER 28, 2001, PULLING TRAILER AT 55 MPH, 8:PM, LEFT SIDE FRONT TRAILER TIRE COMES APART AND TREAD IS IS FLUNG THROUGH THE WHEEL WELL AND INTO THE INSDE OF THE TRAILER. THIS CAUSED OVER $700 OF DAMAGE TO THE TRAILER. APRIL 5, 2001, APPROX 55-60MPH, 7PM, LEFT REAR TIRE COMES APART. THE TREAD COME OFF AND WRAPS AROUND THE AXEL. ON APRL7, 2002, (YES, LESS THAN 48 HOURS LATER) THE RIGHT , FRONT TRAILER TIRE STARTS TO SOME APART. A DRIVER "MOUTHS" FLAT TIRE AND WE PULL OVER JUST BEFORE THE TREAD COMPLETELY COME OFF THE SIDEWALLS. THE TIRES HAVE BETWEEN 4-5,000 ON THEM, ARE 3 YEARS OLD AND WE CHECK THE TIRE PRESSURE BEFORE EVERY TRIP. WE LIVE IN A MILD CLIMATE AND THE TIRES AREN'T SUBJECT TO EXTREME TEMPERATURE CHANGES. THEY ARE COVERED FROM TO KEEP THE SUN OFF. THERE IS NO REASON WE SHOULD HAVE HAD...