Wheels and Tyres186
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 (d epending 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 bodi es from the tyre profile.
•Damage to tyres and wheels is frequently 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 (bulges, splits, etc.) If no visible damage is present, please drive at an appropriately slow speed and carefully to the nearest specialist garage in order to have your vehicle inspected.
•Also protect your tyres from cont act with oil, grease and fuel.
•Immediately replace any dust caps of the valves which have got lost.
•Mark wheels before removing them so that 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 no ise, wear-and-tear and aquaplaning.
Further information concerning the use of unidirectional tyres ⇒page 190.
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 co nsiderably if the tyres are insufficiently or over-inflated and this will have an advers e 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. 154 An opened fuel filler flap with the tyre inflation pressure table
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Breakdown assistance196
– Fit on the spare wheel and tighten the wheel bolts slightly.
–Lower the car.
– Tighten the wheel bolts firmly, alternately and diagonally using the
wheel wrench ⇒page 198.
– Mount the full wheel trim/wheel 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, ensu re that the tyres rotate in the correct direction ⇒page 186.
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. The ti ghtening torque for steel and light
alloy wheels must be 120 Nm.
– Have the defective tyre repaired as soon as possible.
WARNING
It is necessary to observe the guidelines given on ⇒page 188, “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.
Note
•If you find, when changing the wheel, that the wheel bolts are corroded and difficult to turn, the bolts must be replac ed before checking the tightening torque.
•Drive cautiously and only at a moderate speed to a workshop where the tight- ening torque can be checked.
Full wheel trim*
Pulling off
– Hook the clamp found in the vehicle tool kit into the reinforced edge
of the full wheel trim.
– Push the wheel key through the clamp, support the wheel key on the
tyre and pull off the wheel trim ⇒fig. 159.
Installing
– First press the full wheel trim onto the wheel at the valve opening
provided. Then press the full wheel trim into the wheel in such a way
that its entire circumference locks correctly in place.
Fig. 159 Removing the full wheel trim
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