I had to replace a dual pair of Bridgestone R293 tires becouse if irregular wear. Most of the tread had a depth of 9/32 which is about 40% of the original tread. About 14,000 miles earlier I had the steering tires with"cupping" swapped for the outside drive tires as recommended in the Newell documentation. First question, has anyone else had tires "self destruct" so quickly?