The tyre inflation pressure for tyres of the tyre size 205/50 R17, which are inten-
ded to be used with snow chains, is identical to the tyre inflation pressure for
tyres of the tyre size 225/45
R17, see ⇒ fig. 157.
The tyre pressure should be at the highest pressure specified for your vehicle at
all times.
The tyre inflation pressure of the emergency spare wheel R 18 is 420 kPa
(4.2 bar).
Always check the inflation pressure of tyres when cold. Do not reduce the higher
pressure of warm tyres. Adapt the inflation pressure of the tyres accordingly if
your vehicle is carrying a significantly higher payload.
Driving style
Fast cornering, sharp acceleration and braking (squealing tyres) increase wear-
and-tear on your tyres.
Balancing wheels
The wheels of a new vehicle are balanced. There are a wide range of influences
when driving which may result in an imbalance and which makes themselves felt
through vibration in the steering.
You should have the wheels rebalanced since any imbalance increases wear-and-
tear on the steering, the suspension and tyres. A wheel must also be rebalanced
when a new tyre is fitted and each time a tyre is repaired.
Wheel alignment errors
Incorrect wheel alignment at the front and rear will not only increase wear-and-
tear on the tyres but will also has an adverse effect on vehicle safety. Contact
your specialist garage if you notice any unusual tyre wear. WARNING
● If the inflation pressure is too low, the tyre must perform a higher rolling
resistance. At higher speeds the tyre will warm up as a result of this. This can
result in tread separation and even a tyre blowout.
● Immediately replace the damaged rims or tyres.
● Tyres which are 6 years old or more should only be fitted in exceptional ca-
ses and when adopting an appropriately cautious style of driving. For the sake of the environment
Tyres which are insufficiently inflated increase your fuel consumption. Wear indicators
Fig. 158 Tyre tread with wear indicators
The base of the tread of the original tyres has wear indicators 1.6 mm high, instal-
led at right angles to the direction of travel. These wear indicators are located at 6
- 8 points depending on the make and are evenly spaced around the circumfer-
ence of the tyre ⇒ fig. 158 . Markings on the walls of the tyres through the letters
“TWI”, triangular symbols or other symbols identify the position of the wear indi-
cators.
A remaining tread of just 1.6 mm, measured in the grooves of the tread next to the
wear indicators, means that your tyres have reached their legally permissible mini-
mum tread depth. WARNING
● You must have your tyres replaced with new ones at the latest when the
wear indicators have been worn down. The legally permissible minimum tread
depth should be observed.
● Worn tyres do not provide the necessary adhesion to the road surface at
high speeds on wet roads. One could experience “
aquaplaning” (uncontrolled
movements of the vehicle - “swimming” on a wet road surface). 193
Wheels and Tyres Using the system Safety Driving Tips General Maintenance Breakdown assistance Technical data
