My trailer is parked, not used in a couple of months as the boat is on a lift. Noticed yesterday the spare tire had a catastrophic blowout. I last checked inflation back in January before a trip to Taney, and had it at 50#, per specs. I'm guessing the sun caused enough expansion to blow it. But why the spare? BTW the tire was 3 to 4 years old but had never been driven on.