How Long Does a Tire Last?
Carmakers, tire makers and rubber manufacturers differ in their opinions about the lifespan of a tire. The National Highway Traffic Safety Administration (NHTSA) has no specific guidelines on tire aging and defers to the recommendations of carmakers and tire manufacturers. Carmakers such as Nissan and Mercedes-Benz tell consumers to replace tires six years after their production date, regardless of tread life. Tire manufacturers such as Continental and Michelin say a tire can last up to 10 years, provided you get annual tire inspections after the fifth year.
The Rubber Manufacturers Association says there is no way to put a date on when a tire "expires," because such factors as heat, storage and conditions of use can dramatically reduce the life of a tire. Here's more on each of these factors.
Heat: NHTSA research has found that tires age more quickly in warmer climates. NHTSA also found that environmental conditions like exposure to sunlight and coastal climates can hasten the aging process. People who live in warm weather and coastal states should keep this in mind when deciding whether they should retire a tire.
Storage: This applies to spare tires and tires that are sitting in a garage or shop. Consider how a spare tire lives its life. If you own a truck, the spare may be mounted underneath the vehicle, exposed to dirt and the elements.
If your spare is in the trunk, it's as if it is "baking in a miniature oven," says Dan Zielinski, senior vice president of public affairs for the Rubber Manufacturers Association. Most often, the spare never sees the light of day. But if the tire has been inflated and mounted on a wheel, it is technically "in service," even if it's never been used, Gervin says.
A tire that has not been mounted and is just sitting in a tire shop or your garage will age more slowly than one that has been put into service on a car. But it ages nonetheless.
Conditions of use: This refers to how the tire is treated. Is it properly inflated? Has it hit the curb too many times? Has it ever been repaired for a puncture? Tires on a car that's only driven on the weekends will have a different aging pattern than those on a car that's driven daily on the highway. All these factors contribute to how quickly or slowly a tire wears out.
Proper maintenance is the best thing a person can do to ensure a long tire life. Gervin recommends that you maintain proper air pressure in tires, have them rotated regularly and have them routinely inspected.