Your Total
Tyre Supplier

Request login

Aging car tyres & dot-code

With regard to the ageing of car tyres, we follow the standpoint of the Technical Information Platform Tyre Manufacturers (TIP). This is an official advisory body to VACO which advises the General Board in determining positions on technical matters. The following manufacturers represent TIP: Apollo Vredestein, Bridgestone, Continental, Goodyear Dunlop, Hankook, Michelin, Pirelli, Toyo, Yokohama.

Ageing of tyres

The actual ageing of tyres starts only after fitting/use. The advice is to have the tyre checked annually by a tyre specialist 6 years after it has been used. We do not say replace after x years, but replace when serious signs of ageing appear, or when damage occurs.

Situation and problem description

Before tyres are fitted on a vehicle, they are stored for shorter or longer periods of time. Firstly at the tyre manufacturer’s and then at the distributor’s. On the tyre, behind the DOT code, is the production date of the tyre (week and year). A consumer can therefore see when a new tyre was manufactured when it is fitted.

Question to tip

To what extent is a tyre subject to aging due to storage before it is sold and how does storage time affect the condition of a tyre?

Advice TIP: Tyres are stored at the tyre manufacturer’s in optimal conditions. This ensures that the tyres delivered to the distributor are in optimum condition for a full life cycle on a vehicle. The distributor also follows the industry guidelines for storage conditions, which are laid down in ETRTO’s Recommandations document. Tyres stored in accordance with these guidelines are virtually immune to ageing and therefore in the best possible condition when fitted on a vehicle. During storage, a tyre is unloaded, not inflated and only subject to minimal temperature fluctuations. Therefore, the storage time before a tyre is fitted has no real influence on road safety.


The actual ageing of a tyre only starts when the tyre is put into service. The ageing process is influenced by the maintenance and use after the tyre has been fitted on the vehicle.

  • Influence of storage temperature and storage time versus normal use(*)

Studies on the influence of temperature and storage time on the chemical process show that a tyre that travels 60 mph over 12,000 miles (97 km/h over 19,000 km) ages just as much as a tyre that is stored for 17 years at a temperature of 70ºF (21ºC). So the influence of storage time is negligible. In other words, a tyre that is used for one year on a vehicle ages as much as it does during 17 years in storage. Or: 3 weeks of use equals one year of storage. This applies to a well-maintained tyre.

  • Influence of storage temperature and storage time versus operation with undervoltage(*)

At 35% under-inflation, the temperature of the tyre rises to 80 degrees. A tyre ages 63 times faster than a year in storage. In other words, a tyre with 35% under-inflation will age as much in one week of use as a tyre that has been stored properly for a year.

  • Influence of storage temperature and storage time versus high loads in use

After mounting the tyre, the life of a tyre becomes totally different. From that moment on, the tyre is subjected to the influences of high loads, such as braking, steering, deflection, deformation, under-pressure, speed, road impact, high temperatures and the influence of sunlight. All these influences are not present during proper storage. Even when the vehicle is stationary, the tyres are in use, as long as they are inflated and under the vehicle.


The influence of storage time has a negligible influence on the technical characteristics of a tyre. The tyre ages during use, not during storage.

(*) R. G. Altman, E. M. Beutler, J. T. Kohler, “Erroneous or Arrhenius – Potential Impact of Oven Temperature Variations on Laboratory Aging of Tires”, submitted for presentation at the 2009 Tire Society meeting, and for consideration for publication in the journal Tire Science and Technology.

The age of a tyre can be recognised by its dot code

On the side of your tyre is a so-called DOT code. The last four digits after the letters “DOT” tell you when a tyre was produced. The first two digits indicate the week of production, the last two the year.

An example: 1717 means that the tyre was made in week 17 of 2017.

An example: 1717 means that the tyre was made in week 17 of 2017.

This means that the tyre is from before the year 2000. Are your tyres six years old or more? Then it is safe to have them checked annually. Do you have doubts about the age of your tyres? Feel free to ask your VACO tyre specialist.

Source: VACO