I am curious as to what convinced you? I am not saying that they are of no value, but when I had my previous RV parked at a local lake for many years I checked the tires carefully when I did move it out of the campground (multi-years lease) and those tires that were always in the shade, and the tire's sides facing inward (so no sun on them) and the tires that were in the sun everyday showed equal spider webbing on the sidewalls (so I replaced all of them and they were ~6 years old). In other words, I would have expected that the tires in the sun every day would appear to be in worse condition than the ones in the shade everyday. Again, I am not saying tire covers are of no value, more that I am not sure that they are of value from my experience but if you had some convincing evidence then I certainly would give it more thought and perhaps purchase some covers as well. Perhaps the bigger value is keeping the wheels clean? ~CA