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 |
| |
|
Week |
| 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 |
| |
|
Week |
| 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. |
| Tyres must always be renewed when: |
| the legal minimum tread depth of 1.6 mm is reached, |
| there is visible mechanical damage |
|
|
|
The energy loss caused by the deformation of the tyre when
rolling is known as rolling resistance.
With rolling resistance optimised tyres the deform ...
The tyre industry produces tyres with flange protection for
alloy wheels. The flange protection is intended to protect alloy
wheels from damage due to contact with ke ...
Other materials:
Winter tyres
M+S symbol
On an “M and S tyre” the tread profile, tread composition or
construction are designed so that the handling characteristics
are improved on snow as compared with a normal tyre - especially
when pulling away or stabilisatio ...
Introduction
This chapter contains information on the following subjects:
→ Display and indicator lamps
→ Operating the cruise control system (CCS)
The cruise control system (CCS) helps to maintain an individual set speed when
the vehicle is travelling forwards at speeds of more than ...
Seam seals, middle body
Note
Seam seals made during repair work must be identical in
appearance and thickness to the original seam seals.
To avoid damage or faulty operation, brush seam seals smooth
near attachments which must be attached.
...
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Rolling resistance optimised tyres
Tyres with flange protection