The Truth Explained
*Studies were conducted by the Korean Department of Customer Protection; ADAC and The German Motorist Organization. Research by the independent organisations concluded that as long as a tyre is kept in recommended storage conditions, there will be no reduction of performance between tyres recently made and tyres made 3 years ago. Michelin recommends that tyres older than 10 years from the Date of Manufacture be removed from service entirely.
Q: Why is Michelin sharing this information about tyre aging?
A: Because there is widespread misunderstanding of how tyres age.
Remember: The most important date is NOT the tyres’ fabrication date (DOT) but the date of installation on a vehicle.
Q: The tyre does not age significantly if it has not been installed. Why?
A: While in inventory (pre-installation), a tyre is uninflated, unloaded, and subjected only to the relatively minor temperature fluctuations of the storage facility.
Q: If Date of Manufacture does not matter, what date DOES matter?
A: The date that the tyre is installed on the vehicle. During operation, the tyre is subjected to high stresses, road impacts and other conditions which do not exist in storage. Therefore, a tyre ages significantly once it has been installed.
Q: What are some studies that confirm that tyre aging is irrelevant in storage, and is only relevant post installation?
A: Three studies have been done in Korea, Germany, and Saudi Arabia.
The studies in Korea & Germany show no difference in performance between tyres that are newly made versus tyres that are in storage for 3 years. The Saudi Arabia study shows that a tyre used on a vehicle for 1 year has equivalent aging to a tyre in storage for 10 years.
Q: Tyres age post-installation. What does Michelin advise in terms of tyre care post-installation?
A: Post-installation, the tyre requires very special care during its operational life - care that was irrelevant in storage, such as: Pressure maintenance, alignment, damage inspection, tread depth measurement.
Sources: Korean Department of Customer Protection; ADAC, the German motorist organization; Saudi Arabia study conducted by Osaka City University, published in Rubber Chemistry and Technology.