On a really hot summer day, a tire blew out on me as I walked out of the garage. Only thing I can think of was that the extremely hot driveway asphalt caused the air pressure in the tube to increase the tire's limits. No damage to tire., Not realizing what had happened, went back into the garage, changed tubes, pumped up to tire pressure , and when out to driveway, only to blow out another tube! again, no damage to the tire.