When it comes to tires, age is as important as mileage. The degradation of a tire occurs over time, mostly the result of a chemical reaction within the rubber components. That aging process can be accelerated by heat and sunlight. Environmental conditions like exposure to sunlight and coastal climates, as well as poor storage and infrequent use can hasten the aging process.
On the surface, it makes sense that rarely used tires should last indefinitely if they’re properly cared for. However, looks and low miles can be deceiving. The effects of aging may not be visibly detectable. Since there is no standard test to assess the serviceability of a tire, even an inspection performed by an expert may not always reveal the extent of tire deterioration. Vehicle owners are therefore encouraged to have their tires checked after five years of use, then annually thereafter.
There are no hard and fast “expiration dates” on tires, but because rubber begins to crack and deteriorate over time, most experts suggest that eight years is the maximum safe life expectancy of a tire. If you don’t drive your classic at all and it just sits on display, you can get away with keeping the original tires as they’ll hold air. But if you drive the car at all, you need to know how old the tires are.
Poor maintenance is often cited as a cause of failure. While maintenance is important for good wear and safety performance of tires, many other factors contribute to their failure. Tire failures can be caused by a few factors such as under- or over-inflation of tires, overloading of vehicles, road hazards, improper maintenance, structural defects, and improper installation, in addition to tire aging.