VW Golf manuals

Volkswagen Golf Service & Repair Manual: Tyre ageing

Even visually flawless, new or barely used tyres with sufficient tread depth, which are older than six years, may show significant reduction of wet properties and winter suitability due only to ageing.
Tyre tests show that a continuous development process, the use of new rubber compounds and modern raw materials, in conjunction with the optimisation of tread design and tread geometry, make it possible to continually improve tyres.
Only tyres with state-of-the-art technology can meet the requirements of modern and highly developed vehicles and the constantly growing demand from the customer for economical tyres offering maximum possible safety, driving dynamics and comfort.
Tyres age as a result of physical and chemical processes, which can impair the function of the tyres. Tyres which are stored for longer periods of time harden and become brittle faster than tyres which are constantly in use on a vehicle.
Older tyres may develop hairline cracks as a result of ageing.
When tyres are in regular use, the constant flexing activates softeners in the rubber, preventing hardening and the development of cracks.
It is therefore important to take into account not only the tread depth, but also the age of spare tyres, stored tyres and tyres which are not permanently in use.
The tyre age can be determined from the DOT designation, which includes, among other things, the production date of the tyre.
Example of a DOT number to 31.12.1999
DOT ...... 5 0 9 <  
          Stands for 199_
        Last digit is production year
In this example, the production date is the 50th week of 1999.
Example of a DOT number from 01.01.2000
DOT ...... 0 1 0 0  
        Last 2 digits is production year
In this example, the production date is the 1st week of 2000.
It is recommended not to use summer and winter tyres which are older than 6 years anymore. The original properties deteriorate due to the aging process. Winter tyres especially lose their adhesion properties.
When new tyres are fitted, the spare tyre may also be used if it is in flawless condition and is not more than 6 years old. The age of the tyre has a great influence on the high-speed capability of the tyre. It is possible to combine a spare tyre which is several years old with new tyres; however, this can have an adverse influence on car handling.
Tyres are constantly being further developed, which can lead, for example, to slight changes in the rubber compound, even if the tyres are of the same make, size and tread pattern.
All vehicles are factory-fitted with four identical tyres and wheels.
Front-wheel drive vehicles:
For reasons of safety, tyres of the same make and with the same tread pattern should be mounted on one axle.
Four-wheel drive vehicles:
Vehicles with four-wheel drive must always be equipped with four wheels with tyres of the same size, construction, tread pattern and make.
Renewing tyres
Tyres must always be renewed when:
the legal minimum tread depth of 1.6 mm is reached,
there is visible mechanical damage
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