I have sunbrella covers for my trailer tires.
SO is the cape actually to keep the UV off your shirt/pants?
I am just kidding... i have just replaced a tire that had cracks though it.... and need to replace the other one. I may spray 303 on them to help protect them but i doubt i will go so far as to get covers for them.
But just yesterday i was thinking about making a cover for my spin/snuff and maybe even the mast (up to the spin bail).