Back when we purchased the Magne Shades for our windshield and other front windows, we also purchased mirror covers and tire covers.
We used the mirror covers for a while, but don’t bother anymore. And we’d never used the tire covers, since we typically travel every week or so. But while staying at a sunny location for a couple of weeks a while back, we decided to use them, and have been using them regularly since then.
The idea of the tire covers is to protect the tires from harmful UV rays, that can degrade the rubber. We use 303 Protectant on the tires, which also provides UV protection, but more is better.
These EZ Fold Tire Shades are quite nice; they fold up compactly into a handy bag:
And are unobtrusive when in place, only covering the tire itself, not the rims, so you wouldn’t notice them without looking closely:
They are held on by straps that go over the top of the tire, and on either side.