We've been running radials on our '56 for 20 years. Just put on our first set of Cokers (bought from Summit) this spring, then drove it 500 miles heading to Springfield and back this summer. They look good, drive nice, and have a decent price. Going faster than 80 is a lot of work, but that's more because of the old suspension technology than anything else. This is the third set of tires we've put on the car, so obviously we are getting about 10 years on a set (and the last set were not bad, the white was just too narrow). UV is the tire's biggest enemy, followed by tire cleaners that make them shiny. Be careful what you wash them with, and keep it out of the sun and they will last a long time. Technically, it's ozone that breaks them down and UV makes ozone, as well as electric appliances (so don't park it next to your air compressor). I've been getting 100,000+ miles out of radial tires for over 20 years (on other cars) because I take care of them and put the miles on before the ozone breaks them down. We were talking with Wallace Wade back in February (they come to a swap meet up here every year), and he said his only problem in converting to radials was that a 205/75R15 couldn't handle the weight of his Buick. He strongly recommended going up to the 225, but said the 215 would probably be OK. We'd always had 205s on it in the past with no problem, so we went with 215s.