We all likely garage our cars so sun damage is minimal. I believe the Michelins are better quality than the average tire (and though they own BFG, T/As quality is not equal). The tires are still nice and pliable 20 years later. BTW I could not sell the GTX with original wheel covers, so put some Magnum 500s and 37 year old Eagle STs with birds that my brother had laying around and it sold in a month Now those GY tires looked great but were hard static display placeholders. Probably has T/As on it now.
