Are tires that have been stored for 2-3 years considered "expired tires"?

Recently, a tire owner complained that some car owners only buy the latest tires when buying tires, and "sneer" at tires with a long inventory, and think that tires that have been stored for 2-3 years have become "expired tires". Is this really the case? How should tires be stored, what are the factors that affect tire performance, and how long does it take for tires to be considered "expired"?

01. It is inaccurate to say that tires are expired after 2-3 years

At present, there is no standard in the world to determine the expiration date of tires, because the damage to each tire depends on many factors such as temperature, load, tire pressure, speed, and even the road conditions on which the tires are used.

Therefore, it is very inaccurate to hastily assume that tires have expired after only 2-3 years of storage, especially when these tires are well stored and are not affected by any of the factors mentioned above.

The British Rubber Manufacturers Association explicitly recommends not to install new tires that have been in stock for 6 years or more on the car, and requires that all tires that are more than 10 years old from the date of manufacture must be disposed of, whether used or unused.

However, Michelin believes that tires are not as easy to deteriorate as fruits, and the "expiration date" of tires should be calculated from the moment they are installed on the vehicle for use, not from the date of manufacture. Because tires are only affected by the above-mentioned factors and wear when they are installed and used, but not when they are stored.

When the tires are stored, they are zero-load and zero-pressure, but when they are installed on the vehicle, they will be subject to air pressure and driving influences (braking and acceleration, high speed, rough roads, sharp objects, heavy objects, changing weather and temperature conditions, etc.), which have a greater impact on the tires. For example, even when the vehicle is stationary, the tires still have to bear the weight of the vehicle itself.

02. Comparison between new tires and three-year inventory

In order to verify its claims, Michelin has conducted tests in Germany, South Korea and Saudi Arabia to prove that tires that have been in stock for three years can still provide the same performance level as newly produced tires.

The test results in Arabia showed that the performance of tires that have been used for one year is similar to that of tires that have been in stock for 10 years. At the same time, in order to test the characteristics of tire rubber, Michelin stored the tires at a constant temperature of 40 degrees Celsius for 20 years. Compared with tires that have been used for 40,000 kilometers, it was found that the tire rubber stored for 20 years will deteriorate faster when used.

Comparative tests were conducted on new tires and tires that have been stored for three years in South Korea and Germany respectively. The results showed that the difference in performance between new tires and tires that have been stored for three years is negligible. Even so, Michelin agrees with the British Rubber Manufacturers Association that tires that are 10 years or more from the date of production must be replaced or discarded.

03. Tire storage temperature is critical

As mentioned above, tires that have been stored at a constant temperature of 40 degrees Celsius for 20 years are more likely to deteriorate than tire rubber that has been used for 40,000 kilometers. Michelin also pointed out that when storing tires, you must pay attention to the storage conditions. One of the key conditions for correctly storing tires is temperature.

The European Tire and Rim Technical Organization (ETRTO) recommends that tires be stored at a temperature not exceeding 35°C. A study in Saudi Arabia found that tires stored at 50°C aged twice as fast as those stored at 40°C and four times faster than those stored at 30°C.

In fact, tire shops can explain the problem of inventory tires to car owners, so there is no need to worry about "expiration". In addition, tires with a long inventory are often promoted at low prices, which is actually a benefit for car owners. It is safe and reliable, and you can buy it with confidence and save money.