Upgraded to a new pusher Dec. 2007 and had to replace my 2 front Michelin tires on a trip from Fl to the west coast ( tires had 21 thousand miles) and the sidewalls had large cracks, The motor home had set on the dealer lot in Florida for a year before I got it but to have 2 tires fail at the same time. My last motor home had Goodyears on it and I made two trips to Alaska and 5 trips to Ca. and over 50 thousand miles and just replaced them because they were 7 years old, with no problems. I will be taking off the back tires and replacing them with Goodyear before I start to travel next year.