The average life of a tire is determined by the conditions a tire is exposed to throughout its life - not measured in calendar years. Temperature changes, sun exposure, storage conditions, usage, and maintenance schedules all contribute to the rate at which a tire ages.
It is impossible to determine a tire’s exact life expectancy, because there is no way to account for the level of influence any one of these factors may have on a tire. However, you can defer to the vehicle and tire manufacturers replacement recommendations:
To find the age of your tire, you can refer to your tire’s DOT Identification Number, which is stamped on the tire’s sidewall. The last four digits of this number indicate the week and year the tire was built.
- Vehicle manufacturers recommend tire replacement at 6 years
- Tire manufacturers' warranties expire at 6 years
- Tire manufacturers recommend replacement at 10 years, regardless of tread depth
Tire Aging Process
Tires contain anti-aging properties that are mixed into their rubber compounds. Tires contain anti-ozonants that help the rubber stay soft, flexible, and conducive to grip. You may notice this as a “browning” effect on the sidewalls. However, over time, air begins to permeate the tire wall and weaken the integrity of the tire’s structure; causing the tire’s flexible structure to become brittle and lose strength. This deterioration process is known as oxidation, since oxygen serves as the catalyst of decay.
In addition to the degradation caused by the permeation of air and oxygen particles, other factors can cause tires to lose their gripping power and overall effectiveness. Research conducted by the National Highway Traffic Safety Administration (NHTSA) maintains that tires age more rapidly in heat. Warm climates and exposure to direct sunlight can speed up the aging process by accelerating oxidation. Therefore, the tires equipped on vehicles that are stored outdoors will age faster than tires on vehicles stored in a garage.
Tires will also age faster if they are improperly cared for or are abused. If tires are driven while overinflated or underinflated, internal damage could occur that may not be detected through visual inspection. Impacts, punctures, and improper tire repairs may also cause damage that could permanently decrease the life of tires. These occurrences weaken their integrity and contribute to premature aging. To reduce these risks, make sure your tires are correctly inflated, regularly maintained, and treated with respect.
When Should I Replace My Old Tires?
If you commute or drive frequently, you may wear out your tire tread before the rubber deteriorates. Logging over 12,000 miles per year, an average rate for an American driver, may wear tread down to an unusable level within 3-4 years. This regular level of use may necessitate replacement before age and environmental exposure could compromise the rubber compound’s integrity.
Advancements in tread life have made tire aging a more pertinent issue. Some of today’s most advanced tires have a 90,000 mile treadwear warranty. If equipped on vehicles only driven infrequently, they may require replacement before the tread wears completely down. Tires on cars driven exclusively on weekends (i.e., “garage queens”), or collector vehicles all face an increased risk of accelerated aging. Be prepared to replace these tires within 6-10 years, no matter how much remaining tread they possess.
Sometimes you may notice spider web cracks in the sidewalls or tread, but not always. Many automakers assert that tires be replaced as soon as they become six years old. Tire experts contend that tires- if properly stored and cared for– can last anywhere from 6-10 years.
Extending the Life of Your Tires
In order to ensure maximum tire life, it is important to have your tire maintenance performed regularly. Follow these steps to improve the life of your tires:
- Check your tire inflation pressure every 3,000 miles. This will not only extend the life of your tires but also help with vehicle handling, acceleration/deceleration and fuel efficiency.
- Rotate your tires every 6,000-8,000 miles to promote even treadwear.
- Get your wheel alignment checked, as specified in your vehicle's owner's manual, or if you begin to feel the vehicle "pull” to any one side or the other..
- Check your tires regularly for any road debris or damage.
- Inspect your tires for any irregularities in treadwear, as these could indicate problems with your vehicles alignment or inflation.
- Be sure not to exceed a tire’s maximum load capacity, as this puts excessive pressure on your tires.