Originally Posted by
SquidPuppet
That is exactly my point. It IS a waste of money and it IS the tire's fault. Four years is way too short. I have tires that are 16 years old on a bike that's only ridden about 200 miles each summer. It's stored in sub freezing temps for months on end in the winter and is exposed to 100+f sunshine all summer. No cracks in the sidewalls. No indication of decomposition. Good tires are good tires. Tires of low quality rubber fall apart prematurely. I know they exist because I've had a few sets, and won't buy the brand that let me down again.
Ozone exposure is as much, if not considerably more, of a factor in the longevity of rubber:
https://en.wikipedia.org/wiki/Ozone_cracking
In qualifying many automotive components, ozone exposure is a test defined by ISO and utilized by most of the OEMs. I can run plastics in a thermal chamber and run them from -40C to 105C for weeks at a time, with little change in appearance, but ozone can easily destroy those same parts.