Ultra Violet light, constant moisture, Ozone, and age are enemies of tires. The biggest problem with tires right now is that the materials the manufacturers are using do not last as long as those manufactured long ago. Although the new tires can last for up to 80,000 miles, they have a finite lifetime of only 4 or 5 years, before they degrade to the point of becoming a liability. Here in NJ, it is illegal for a tire shop to sell a tire that is more than 4 years old. Tires have a date code molded into the sidewall, and some shops will not even mount tires more than 4 years old (when changing from snows to standards and back), even if they look good. Another factor is tire design. Standard auto tires must NOT be used on trailers! The forces generated against the sidewall of a trailer are up to 70% greater than those on a common auto, especially on multi-axle trailers. The extra force generates heat, and will blow out the sidewalls long before the tread is worn out. Trailer tires are specifically built to handle this extra load. Covering the tires, with a non moisture holding material, and taking the load off, when storing long term certainly with prolonging tire life, but the time issue will not be solved until the tire makers come up with better compounds for tire construction. Remember programmed obsolescence? The tire manufacturers want the tires to wear out within a certain time frame, so that you will have to buy new ones! If the tires don't wear out, how will the manufacturers make money?
