Wheels and Tyres223
Using the systemSafetyDriving TipsGeneral MaintenanceBreakdown assistanceTechnical Data
Wheels and Tyres
Wheels
General comments
•New tyres do not offer optimal grip at first and should therefore be run in for
about 500 km at a moderate speed and an appropriately cautious style of driving.
You will also profit from longer tyre life.
•The tread depth of new tyres may differ because of design features and the
configuration of the tread (depending on the type of tyre and the manufacturer).
•Drive over curbs on the side of the road and other such obstacles slowly and,
where possible, at a right angles in order to avoid damage to tyres and wheel trims.
•Inspect your tyres from time to time for damage (punctures, cuts, splits and
bulges). Remove foreign bodies from the tyre profile.
•Damage to tyres and wheels is frequent ly not visible. Unusual vibrations or
pulling of the vehicle to one side could be a sign of tyre damage. Please reduce
your speed immediately and stop if you suspect that a wheel is damaged.
Inspect the tyres for signs of damage (bulge s, splits, etc.) If no visible damage is
present, please drive at an appropriatel y slow speed and carefully to the nearest
specialist garage in order to have your vehicle inspected.
•Also protect your tyres from contact with oil, grease and fuel.
•Immediately replace any dust caps of the valves which have got lost.
•Mark wheels before removing them so th at their previous direction of running
can be maintained when mounted them again.
•Always store wheels or tyres which been removed in a cool, dry and, where
possible, dark place. Tyres which are not fixed to a wheel trim should be stored
upright.
Unidirectional tyres*
The direction of rotation of the tyres is marked by arrows on the wall of the tyre. This
indicates the direction of rotation of the tyre, and it is essential that the tyres are
fitted on to run in this direction. Only then are the tyres able to provide the optimal
properties in terms of grip, low noise, wear-and-tear and aquaplaning. Further information concerning
the use of unidirectional tyres ⇒page 227.
WARNING
•New tyres during the first 500 km do not offer optimal grip and should
therefore be run appropriately - risk of accident!
•Never drive with damaged tyres - risk of accident!
Note
Please observe the various differing legal requirements regarding tyres.
Tyre life
The life of your tyres very much depends on the following points:
Tyre pressure
The working life of tyres will be shortened considerably if the tyres are insufficiently
or over-inflated and this will have an adverse effect on the handling of your vehicle.
Correctly inflated tyres are of partic ular importance when travelling at high speeds.
It is therefore good to check the pressure at least once a month and also before
Fig. 204 An opened fuel
filler flap with the tyre
inflation pressure table
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Breakdown assistance
234
WARNING
•If you find yourself in flowing traffic switch on the hazard warning lights
system and place the warning triangle on the side of the road at the
prescribed distance from your vehicl e while observing all national legal
provisions. In this way you are protecting not only yourself but also other
road users.
•Never start the engine with the vehicle sitting on the raised jack - danger
of suffering injury!
Caution
If you have to change a wheel on a slope first block the opposite wheel with a stone
or similar object in order to secure th e vehicle from unexpectedly rolling away.
Note
Comply with the national legal regulations.
Changing a wheel
Always change a wheel on a level surface as far as possible.
– Take off the full wheel trim* ⇒page 235 or the caps ⇒page 235.
– In the case of light alloy wheels remove the wheel trim cap ⇒page 236.
– Slacken the wheel bolts ⇒page 236.
– Jack up the vehicle until the wheel to be changed is clear of the ground
⇒ page 237.
– Unscrew the wheel bolts and place them on a clean surface (cloth, paper etc.).
– Take off the wheel. – Fit on the spare wheel and tighten the wheel bolts slightly.
– Lower the car.
– Tighten the wheel bolts firmly, al
ternately and diagonally using the
wheel wrench ⇒page 236.
– Mount the full wheel trim/w heel trim cap or the caps.
Note
•All bolts must be clean and must turn easily.
•You must never grease or oil the wheel bolts!
•When fitting on unidirectional tyres, ensure that the tyres rotate in the correct
direction ⇒page 223.
Subsequent steps
After changing the wheel, you must perform the following steps.
– Stow and attach the replaced wheel in the spare wheel well.
– Stow the vehicle tool kit in the space provided.
– Check the tyre pressure on the spare wheel just mounted as soon as
possible.
– Have the tightening torque of the wheel bolts checked with a torque
wrench as soon as possible. Steel and light alloy wheels must be tight-
ened to a tightening torque of 120 Nm.
– Have the defective tyre repaired as soon as possible.
WARNING
It is necessary to observe the guidelines given on ⇒page 225, “New tyres
and wheels” if the vehicle is subseq uently fitted with tyres which are
different to those it was fitted with at the works.
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