Originally Posted by Gary RVRoamer
This says they age faster at higher temperatures, but doesn't necessarily mean they only last half as long. Aging of the rubber is but one factor in the useful life of a tire and it is debatable whether it is even a significant factor. We cannot say, for example, that a tire that is NOT COVERED will last 10 years, but a tire that is COVERED at every opportunity will last 20 years. Too many other factors come into play to try to isolate just one of them. At best we can say that covering a tire may help it last longer. MAY.
I agree. I didn't mean to imply that covering tires would double their life and counteract all other things that reduce tire life BUT I do believe, based on Science (yes I am a "Scientist") that excess heat can REDUCE tire durability significantly.
Rubber needs to bend and stretch as you drive. If it can't it will tear and break. With enough tearing parts (belts for example) can come apart.
I have seen tires fail with belt separations with zero miles where just the inflation pressure and heat degradation allowed the belt forces to exceed the belt rubber strength.
There are a number of pictures of external mount spare tires failing with belt separations. Always on the Top side. Now maybe the failing on the side with most direct exposure to the Sun's heat is just bad luck in that the manufacturing defects just always ended up being on the top side but I think the odds are against that.
Tire covers protect from UV AND can reduce heat.
IMO a solid black cover that wraps around the tire might be worse as with no air circulation the heat is trapped and goes into the tire.
However based on measurements I did last Aug Black or dark screen covers that hang off the side of the RV as seen in the picture in post #16 can work fine as the tire does not heat up.
If you have the solid vinyl covers then White is the way to go.
I would rather sacrifice a cover than cut the life of a tire by a year or two. Do the math. Assume 7 year or 8 year tire life. Does a cover cost 1/7 th the price of a tire
My covers are 7 years old (I live in Ohio) and are not looking great. Just replaced my 2 fronts and will probably replace the 2 covers I use (Sun is usually on one side so I only use 2 covers)
My tires have zero cracking but am planning on doing a three year purchase cycle of 2 tires a year with newest always going on the front.