So I'm on a stupid road trip to move my cousin. 3/4 ton ford tow rig doing great. Borrowed my mothers horse trailer and am told the tires are "almost new". I check all the pressures (OCD about that) and set off. 650 miles up to get him all appears good. 250 miles back under load and we stop for gas, I check the tires and hear hissing from the passenger side front axle.
Long story short, both tires on that side had failed. Within 15 minutes front was flat and rear was leaking around a plug. I nurse it over to a tire place for two new tires. Steel belts had come out, broken inside, just a mess.
Talked to tech (tremendously helpful guy) about why. He said that it looked like really old tires (4years old via the stamp) and they were a brand he'd never heard of. Mom admits they are parked in a way that the right side is exposed to a lot of sunlight.
I'm glad I caught the problem when I did though, another 10-15 minutes on the highway would have been fairly catastrophic and a much more expensive PITA to repair.