Bike tires

On our way to the Smokies today, we stopped at a Subway and ate outside where a lady had parked her bikes. During the middle of our meal there was a tremendously loud "pop" from her direction. I thought she had a gun and it had gone off. It turned out to be the front tire on her bike. As our ears rang and we talked about her biking trip and her fortunate ability to replace the ruptured tire with a spare, something extremely unexpected happened. As I was looking at the bike, the second tire exploded, releasing a puff of condensed air along with an equally loud noise. It was literally no more than two minutes after the first tire had gone. She had ridden some 45 miles and had her bike parked in the sun, but it still seems incredible for both tires to go in such a short time span. (She ended up calling her husband to pick her up in his truck, and my friend and I continued on our way.)