[cycop]

I had to replace my pair of $250 shoes every 3 to 4 months once I started running 50KM a week. The waste factor of having to throw those shoes out every time. Seems like I went though much more rubber than the 4 tires on my car over the lifetime of the tires of around 60,000KM

[grogenaut]

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.