I went to pick up my 5th wheel from storage to prep it for a trip and found that the spare tire had self destructed. I recently replaced all the other tires with Goodyear Endurance ST225/75 R15E, but decided to keep the original Castle Rock spare that came with the trailer as my spare. It has 0 miles on it, has never touched the asphalt. The reason that I replaced the other Castle Rocks was because we are going to be travelling this summer and I didn't trust the original tires, even though they only have about 2000 miles on them. My wife thought I was just being paranoid and wasn't too happy when I spent $500 on new tires to replace new tires, but she sees my point now