bought a slightly used class c. 4 years old, exceptionally low mileage. everything looks new. no wear seen anywhere. except the tires. the air pressure was just 30 psi on load level E (80 psi max). tread wear looked "like new". i imagined this to be the find of the century. great price. I brought them up to proper pressure and gave them little more thought. the wheel allinement was perfect and all bearings and such were "like new". after driving 10,000 miles, two tires (one front, one rear) blew or rather, delaminated, sending large chunks of tread and steel belts everywhere. lucky, no body damage. lucky, i felt some warning vibration and slowed down to 20 before it happened, thus avoiding loss of control. i am replacing all tires. the old tires were made by general and were oem. investigation showed the previous owner always drove at 30 psi for a more comfortable ride. i have talked to many rv'ers since and discovered this to be a common practice. this is an extreemly dangerous thing to do. maintain your tires as though your life traveled there on. find out the recommended tire pressure and use it.