GamblerGORD53

That WAS true for tires made from about 1990 to 2010 and maybe now for some cheap brands, IDK. I had some that died in 3 years, the corners just disintegrated. I think they were Specialized made. They did have a different color sidewall that would mostly cause that. They did something weird to the rubber those years. Since I started using Schwalbe they last until the road wears them out, NEVER had one crack.
OTOH ... In 2017 I bought a mostly shiny 1973 CCM SA 3 speed. Turns out it had the plastic cap on the spring missing, so working poorly and got shelved for 40 years.
I decided to build new 650B wheels and did the rear right away, and both new tubes. But then I waited for the OLD nylon front tire to wear out, might have been the original tire. It went 1,930 miles, till I decided on this last 76 mile ride, a nail and prying the tire finished it off. Wobbled all the 26 miles home. LOL. Second last ride I took it to Jasper on a 2 day car trip. I climbed the hill better than the rental MTBs. LOL.
As for newer tires, I bought a Marathon in 2014 and just started using it in 2022. Rides as good as any new one. Any hardening actually helps toughen it.
After I got CCM tire home LOL. Half the missing chunks happened with the last dismountings, I guess. >>>



The nut holding my front caliper together disappeared, so I had to limp back 5 miles to town. Rode salmon side looking for it. LOL.