As the only part of your vehicle that has direct contact with the road, your tires have their work cut out for them. But it's not just the various stresses that come with rubber meeting the road that can wear on your tires. In addition to physical contact with varying road surfaces, there's also extreme heat and cold, corrosive brake dust, acid rain and even direct sunlight to contend with. Needless to say, your tires can age quickly regardless of tread wear.
What Causes Tires to Age
Most passenger car tires are good for up to 60,000 miles. At roughly 15,000 miles per year, that equals to around 4 years. While tread wear is considered a big factor for tire aging, there are other ways that a tire can get old before its tread is completely used up:
- Normal oxidation – Ordinary oxidation robs rubber of its natural flexibility over time, allowing cracks to slowly form along the sidewall and other portions of the tire.
- Improper inflation – Inflating a tire too much or too little can cause damage to the sidewalls, encouraging cracks to form and spread.
- High-speed and high-performance driving – Taking tires to their limit through high-speed cornering, braking and high-speed driving raises their internal temperature, making it more likely for cracks to form.
- Chemical and physical abrasion – Parking against curbs can easily introduce cracks in your sidewall over time. Overusing certain tire dressings can also strip part of a tire's anti-oxidation protection, leaving it more vulnerable to cracking.
- Exposure to direct sunlight – Ultraviolet light emitted by the sun can slowly but surely degrade rubber and other polymers. For this reason, a vehicle that spends most of its life outdoors and in direct sunlight often fairs worse in tire wear than vehicles stored in a garage or a well-shaded area.
- Exposure to high levels of ozone – In areas with higher levels of pollution, high ozone levels can encourage faster aging of tire surfaces.
Fortunately, most cracks tend to be superficial and cosmetic in nature. The real trouble starts when cracks travel deep enough to reach the inward portion of the sidewall. This can drastically increase the likelihood of sudden tire failure if left unaddressed.
How to Slow Down the Aging Process
In most cases, simply driving your car as normal can help stave off cracks and other cosmetic signs of tire aging. As the miles add up, anti-ozonant incorporated into the rubber slowly migrates towards the surface of the tire. Although this protects the tire from oxidation, it also leaves behind an unattractive brownish "bloom."
A quality tire dressing can help hide the bloom from view. However, you should also be careful when using tire cleaners and dressings. Stick to products that not only feature gentle detergents but also UV radiation blocking agents that ward off sunlight-induced oxidation.
When you're parked for the day, it's a good idea to keep your vehicle in a garage or a shady spot where direct sunlight exposure is less likely. If you own a recreational vehicle (RV) and have it parked for the season, a high-quality set of wheel covers can shield your tires from the sun.
Proper inflation is also a key factor in keeping cracking and dry rot at bay. Tire pressures should be checked at least once a month and only when the tires are cold, as air tends to expand when subjected to heat. When checking and inflating your tires, you should go by the tire information located on the driver side door jamb or within the owner's manual and not by the maximum tire pressure listed on the sidewall.
Know When to Hold...and When to Fold
Keep in mind that severe tire cracking and crumbling could spell the end for your car's tires. If it's been over 6 years since you last replaced your tires and they're showing signs of severe dry rot, it may be time to swap them out for a brand-new set. If your tires are actually crumbling apart or have a slow leak, you'll want to replace them as soon as possible.