It not just sun that can cause damage. The glue inside can fail over time. I had 2 BFG failures:

1)Tires were pushing 18 years old on my ’71 GTX. Looked perfect on the outside, tons of treat left. Vehicle only driven to cruises, etc under 65 mph usually. One day about 1 mile into my ride felt a strange sensation, like a driveshaft or u-joint, or tire low on air. Wasn’t too strong, but concerning. Got out looked around at the tires to see if maybe one was low on pressure, all appeared ok. Got back in and another 3 miles or so at 55mph and got a sudden wild vibration and then as I was slowing down BANG. Right rear tire let go. Lucky it did not take out my ¼ or wheel lip molding. It was like the layers inside just let go in a section.

2)These tires were on my driver Cordoba, which I used a lot up to about 20K miles then the car sat for about 10 years and saw occasional use (parked indoors). Again tires looked perfect, but had 20K of wear on them as expected. Decided to take to work one day and at 70 mph I had a hopping in my front end that was unreal. Pulled over and looked at my tire and it was literally twisting. The tread was wobbled over like 1” about ¼ way around. I put on the spare and got to work. The belt shifted over, which I again think was due to internal failure of the bonding glue inside. Got all 4 new tires, which stunk, since they are 245/65/15, which I found out are hard to find.

So my experience is different than others. I did put BFGs back on, since I cant say it was an inherent failure, but now I am more cautious about age of tires.