I bought an old bike a few years ago with Schwinn tires that are probably about that vintage but were not original to the bike. I believe they were Schwinn Continentals. I usually bring a bike home and if the tires hold air, I will go for a spin around the block. There was about a two or three inch long piece of tread that I could lift up and look at the threads. I didn't have time to get to the bike right away, but it was in very good condition and I would take it out once in a while around the neighborhood with my grandson. One day I got a wild hair and rode it about 23 miles along the MUP to get coffee. But God looks out for babies, old folks and fools so I never had an incident. The Paselas I replaced them with don't hold a candle to the ride those old tires gave but I couldn't keep pushing my luck.