[Christ]

I don't know for sure, but it looks like that cover actually covers down to the widest section of the tire's sidewall, meaning that would be a "normal" sized wheel, and part of the tire is covered. This is entirely possible, because at speed, the amount of air that could get behind the wheel cover wouldn't even be a breath to the average human. You'd want to keep your tires fully inflated, though, or risk damage to the (very expensive) covers.