your shoe rubber is going to be a totally different makeup than car tires. I'm not a rubber chemist so I can't say which is worse. Running in car tires would be

your shoe rubber is going to be a totally different makeup than car tires. I'm not a rubber chemist so I can't say which is worse. Running in car tires would be like running in hard soled work boots. Also I'm betting that < 1% of the population runs as much as you, whereas > 1% of the population has a car or ridses in motorized vehicles using rubber tires.