What causes my motorhome and boat trailer tires to crack?

Ultraviolet light and ozone are the key factors that make tires crack. Tires that are not used frequently, like those on trailers and motorhomes, are more likely to crack than tires on your everyday car. Tire manufacturers include a wax-type component built into the rubber that releases as the tire is used. This component protects against ozone. The problem with motorhomes, boat trailers, and collector cars that don't get used often is that the wax isn't released. Tire manufacturers also include a component called carbon black to protect against ultraviolet (UV) light. To slow the cracking process, cover the tires when stored outside. Before storing for long periods of time, use a tire protectant that contains UV stabilizers.  more