Tire aging occurs very slowly to new tires through chemical and physical processes only if the tire is stored properly. When stored under the recommended conditions (cool, dry, away from direct light, chemicals and ozone sources), a tire will maintain its original performance characteristics over a long period.

A properly stored, unused tire up to 5 years old can be sold as a new tire and placed into normal service if no local legal regulations are opposed to it. Note: The warranty period begins with the purchase date of the tire.

Continental recommends that all tires that are over 10 years old (as shown on the tire’s date stamp) should be replaced with new tires. 

The chronological age of any tire can be found on one of the tire sidewalls by examining the four-digit manufacturing date stamp.

Usually but not exclusively, the date stamp follows the “DOT” marking and manufacturer related alpha numeric digits.

The last four numbers of the entire string identify the date of manufacture. The first two of these four numbers identify the week of manufacture (which range from "01" to "53"), the last two numbers identify the year of manufacture (e.g., a tire with the information "DOT XXXXXXX4521” was manufactured in the 45th week of 2021). 

The tire industry has long recognized the importance of the consumers’ role in the regular care and maintenance of their tires. The point at which a tire is replaced is a decision for which the owner of the tire is responsible. The tire owner should consider factors such as service conditions, maintenance history, storage conditions, visual inspections, and dynamic performance. The consumer should consult a tire service professional with any questions about tire service life.

The following information and recommendations are made to help to decide when a tire needs to be changed. 

Tires are designed and built to provide many thousands of miles of excellent service. For maximum benefit, tires must be maintained properly to avoid tire damage and abuse that may result in tire disablement. The service life of a tire is a cumulative function of the storage, stowing, rotation and service conditions, which a tire is subjected to throughout its life (load, speed, inflation pressure, road hazard injury, etc.). Since service conditions vary widely, accurately predicting the service life of any specific tire in chronological time is not possible.

The consumer plays an important role in tire maintenance.

Tires should be removed from service for numerous reasons, including tread worn down to minimum depth, damage or abuse (punctures, cuts, impacts, cracks, bulges, underinflation, overloading, etc.). For these reasons’ tires must be inspected routinely, at least once a month. Regular inspection becomes particularly important the longer a tire is kept in service. If tire damage is suspected or found, Continental recommends that the consumer have the tire inspected by a tire service professional. Consumers should use this consultation to determine if the tires can continue in service. This routine inspection should occur whether the vehicle is equipped with a tire pressure monitoring system (TPMS) or not.

Consumers are strongly encouraged to be aware of their tires’ visual condition. Also, they should be alert for any change in dynamic performance such as increased air loss, noise or vibration. Such changes could be an indicator that one or more of the tires should be immediately removed from service to prevent a tire disablement. Also, the consumer should be the first to recognize a severe in-service impact to a tire and to ensure that the tire is inspected immediately thereafter.