2007 PROHAULER TRAILER 614SLTD Tiressidewall Problems

I HAVE GOODYEAR MARATHON ST 225/75/15 D TIRES ON BRAND NEW (MAY 2007) 2007 CARMATE 24 FOOT TRAILER. I DROVE THE TRAILER TO SALT LAKE CITY (SLC), BACK TO FREDERICK, MD, THAN BACK TO SLC. SO, WITH ABOUT 8,000 MILES (JULY 14 NOW) ON THE TIRES - I NOTICE "AIR BUBBLES" IN THE SIDEWALL JUST ABOVE THE RIM. I CALL LOCAL GOODYEAR DEALERS, AND NONE HAVE THE TIRES IN STOCK (I DO HEAR THOUGH THAT THIS IS A COMMON PROBLEM WITH THESE TIRES, SEVERAL NON GOODYEAR DEALERS TELL ME THAT THEY HAVE IMMEDIATELY TAKEN THESE TIRES OFF DUE TO ISSUES WITH THESE TIRES). I DECIDE TO PUT THE SPARE TIRE ON (ALSO A MARATHON) AND CONTINUE MY JOURNEY TO SIERRA VISTA, AZ. NEAR PRICE, AZ I NOTICE ANOTHER "AIR BUBBLE" IN A DIFFERENT TIRE. NOT WISHING TO TAKE A CHANCE ON A BLOW-OUT (NO GOOD SPARE TIRE LEFT) I BUY...