Tire age
@413 post 29 shows a tire that the cords are intact but the tire seperate from itself.
To me this indicates that the bond between the cords and the tire rubber was not strong enough.
The inside and outside of the tire might have been perfect, but the inner construction was falling apart.
I pulled the a piller trim off my dart the other day. There is foam tape in there. It was trying to grease!