Everything was fine at first. They felt good, strong and flexible. The strap that runs behind the tire is great for keeping the cases in place in windy areas. Mostly they are strapless. In fact, we only fasten the strap in winter when we know we won't get a camper. The rest of the time they are tight against the hoop without moving. Single tires are much easier to set up and take down than double tires. However, after about a year they started to crumble. They kept getting worse. I'm not sureβ¦