Tire Blowout problems of the 2006 Mazda MAZDA3

The contact owns a 2006 Mazda3. The vehicle has four goodyear dunlap sp sport signature tires, size 205/50r/17 93v, dot mk7prnhr. The contact noticed a crack in the sidewall of the front drivers side tire. The tire was replaced by the dealer. While driving approximately 50 mph, the rear passenger side tire blew out and the contact discovered that the sidewall was also cracked. Upon further inspection all of the remaining tires on the vehicle were also exhibiting unusual cracks in the sidewall. The dealer agreed to prorate the cost of the tires at the contacts expense. The tires were not replaced. The contact stated that the vehicle currently had four different brands of tires on it. The failure mileage was approximately 6,000 and the current mileage was unknown.