Tires, Aging

Tires age as a result of physical and chemical processes whereby the function can be impaired. Tires which are stored for longer periods of time become harder and brittle faster than tires which are constantly in use on a vehicle. Older tires may develop hairline cracks from aging. When tires are in constant use, the flexing activates softeners in the rubber which prevents hardening and the development of cracks.

Therefore, one should note not just the tread depth but also the age of spare tires, stored tires and tires which are not constantly in use. Tire age can be determined by the DOT code which contains, among other things, the production date of the tire.

Example of a DOT code:

In this example, the production date is the 50th week of 2002. Up to 12/31/1999, the DOT number was three digits.

Recommendation:

• We recommend using tires that are older than 6 years only in the case of an emergency and with a cautious driving style.
• When new tires are fitted, the spare tire may also be used if it is in flawless condition and is not more than 6 years old. The age of the tire has a great influence on the high-speed capability of the tire. The combination of a spare tire which is several years old with new tires is possible, but it can influence the car's handling.
• Tires are constantly being developed; this can lead to, for example, slight changes in the rubber compound, even if the tires are of the same make, size and tread.
• For driving safety reasons, tires of the same make and with the same tread should be mounted on one axle.
• AWD vehicles must always be equipped with four wheels with tires of the same size, construction type, tread pattern and make. Excluded from this are vehicles which were delivered by Audi AG with different tire sizes on the front axle and rear axle.