Tire covers, also called tire guards or tire protectors, slip over wheels to shield them from weather and harmful ultra-violet (UV) rays that can prematurely age rubber. Ungaraged vehicles, especially those that get driven less often, are at higher risk to develop cracked sidewalls from sitting in the sun. Tire covers can protect your investment by blocking UV and retarding the aging process.
There is no greater enemy of rubber than UV and ozone. To combat these environmental effects, tires are made with a "competitive absorber" known as carbon black. This compound is what gives tires their color. The molecules in carbon black absorb UV rays converting them to heat that can dissipate off the tire. Over time, however, carbon black becomes depleted and the rubber turns gray and brittle. By shading tires with UV-blocking covers, you are effectively extending the life of tires.
Tires that sit for long periods are even more susceptible to UV damage because driving actually helps tires remain supple. When a tire is driven the flexing of the rubber causes it to become heated, stretched and worked; a “kneading” process that stirs protective wax compounds that rise to the surface, keeping the rubber protected and in good shape. Without flexing, tires become prime candidates for premature breakdown. Add constant exposure to UV rays and the aging process is accelerated.
While it’s good to know what is best for a tire, it isn’t always practical or even possible to garage all vehicles and drive them regularly. Stored or stationary vehicles like motorhomes and trailers are at particular risk of developing tire problems. A good set of tire covers is the next best thing when garaging isn’t possible. Covering the rubber with a UV shield will help preserve the natural oils and compounds in the rubber, and slow the rate of carbon black depletion.
Tire covers come in many sizes to accommodate all tires. The cover slips over the top of the tire reaching about one-third of the way down the backside of the wheel. The front side of the cover extends like an apron to the ground to ensure there is no rubber exposed. Covers are commonly made from vinyl with a soft inner lining and rip-stop nylon stitching. Steel grommets placed at either edge of the apron’s bottom can be fitted with a bungee cord around the back of the tire to keep the cover in place, even in high winds.
Tire covers traditionally come in white or black, with some people opting for white to minimize heat build-up against the tire's face. Others prefer black covers because they don’t show the dirt and are easier to keep clean. It is important to note that not all types of material block UV. Tire covers that block UV should state this on the packaging.
If your vehicle has a rear-mounted spare tire, it is also at risk of early destruction by sun and lack of use. Spare tire covers can be vinyl or metal, and are designed specifically for rear-mounted wheels. Since these protectors are worn 24/7, they are often made with a logo or custom design to add a little color and style. Metal spare tire covers usually incorporate a locking mechanism to discourage theft and will probably require special ordering.
Standard tire covers are available from many auto parts retailers and outlets that specialize in RV equipment. Discount department stores also frequently carry tire covers, which are usually sold in pairs. Look for brands that offer a guarantee of two or more years. Sale prices can start as low as $20 US Dollars (USD) for a set of two standard covers, while a single spare tire cover with a design might be $40 USD or more.