241
Wheels and tyres
WARNING
● Never adjust tyre pressure when the tyres are hot. This may damage
or even burst the tyres. Risk of accident!
● An insufficiently inflated tyre flexes a lot more at high speeds and
causes significant heating of the tyre. Under these conditions, the tyre
bead may be released or the tyre may burst. Risk of accident!
For the sake of the environment
Under-inflated tyres lead to increased fuel consumption and tyre wear.
Significant tyre pressure loss
The tyre symbol is displayed and indicates that the tyre pressure
of at least one tyre is insufficient.
– Stop the vehicle.
– Switch the engine off.
– Check the tyre(s).
– Change the wheel if necessary ⇒
page 250. Tyre useful life
The useful life of tyres is dependent on tyre pressure, driving
style and fitting.
Fig. 166 Tyre tread wear
indicators
Fig. 167 Diagram for
changing wheels
Safety FirstOperating InstructionsPractical TipsTechnical Specifications
242Wheels and tyres
Wear indicators
The original tyres on your vehicle have 1.6 mm high “tread wear indicators”
⇒ Fig. 166, running across the tread. Depending on the make, there will be
6 to 8 of them evenly spaced around the tyre. Markings on the tyre sidewall
(for instance the letters “TWI” or other symbols) indicate the positions of
the tread wear indicators. The minimum tread depth required by law is
1.6 mm (measured in the tread grooves next to the tread wear indicators).
Worn tyres must be replaced. Different figures may apply in export countries
⇒
.
Tyre pressure
Incorrect tyre pressure causes premature wear and could cause tyre blow-
out. For this reason, the tyre pressure should be checked at least once per
month ⇒ page 239.
Driving style
Fast cornering, heavy acceleration and hard braking all increase tyre wear.
Changing wheels around
If the front tyres are worn considerably more than the rear ones it is advisa-
ble to change them around as shown ⇒ Fig. 167. The useful life of all the
tyres will then be about the same time.
Wheel balance
The wheels on new vehicles are balanced. However, various factors encoun-
tered in normal driving can cause them to become unbalanced, which re-
sults in steering vibration.
Unbalanced wheels should be rebalanced, as they otherwise cause exces-
sive wear on steering, suspension and tyres. A wheel must also be reba-
lanced when a new tyre is fitted. Incorrect wheel alignment
Incorrect wheel alignment causes excessive tyre wear, impairing the safety
of the vehicle. If tyres show excessive wear, you should have the wheel
alignment checked by a Technical Service.
WARNING
There is a serious danger of accidents if a tyre bursts during driving!
● The tyres must be replaced at the latest when the tread wear indica-
tors are worn ⇒ page 242. Failure to do so could result in an accident.
Worn tyres do not grip well at high speeds on wet roads. There is also a
greater risk of aquaplaning.
● At continuously high speeds, a tyre with insufficient pressure flexes
more. This causes it to overheat. This can cause tread separation and tyre
blow-out. Risk of accident. Always observe the recommended tyre pres-
sures.
● If tyres show excessive wear, you should have the running gear
checked by a Technical Service.
● Keep chemicals such as oil, fuel and brake fluid away from tyres.
● Damaged wheels and tyres must be replaced immediately!
For the sake of the environment
Under-inflated tyres will increase fuel consumption.
243
Wheels and tyres
Run-flat tyres
Run-flat tyres allow you to continue driving even with a
punctured tyre, in the majority of cases.
In vehicles that are factory-fitted with run-flat tyres 1)
the loss of tyre
pressure is indicated on the instrument panel.
Driving with run-flat tyres (emergency running)
– Leave the ESC/ASR on (Electronic Stability Control), or switch it
on ⇒ page 189.
– Continue driving carefully and slowly (80 km/h (50 mph) maxi-
mum).
– Avoid sudden manoeuvres and sharp turns.
– Avoid driving over obstacles (for example kerbs) or potholes.
– Pay attention if the ESC/ASR activates often, if smoke comes
from the tyres or there is a smell of rubber, the vehicle vibrates
or there are clattering noises. If any of these occur, stop the ve-
hicle.
The run-flat tyres have a tag on the side of the tyre, with the description:
“DSST”, “Eufonia”, “RFT”, “ROF”, “RSC”, “SSR” or “ZP”.
The sides of this type of tyre are reinforced. When the tyres lose air they are
supported on the sides (emergency driving).
The loss of pressure in the tyre is shown on the instrument panel. You can
then drive a maximum of 80 km (50 miles) and if the circumstances are fa-
vourable (for example, low load), even more. The damaged tyre should be changed as soon as possible. The rim should
be checked in a specialised workshop to detect possible damage and re-
place it if necessary. We recommend you contact Technical Service. If more
than one tyre is being used under emergency conditions, this reduces the
distance which can be travelled.
Starting driving in emergency conditions
When loss in tyre pressure is displayed on the instrument panel, this means
that at least one tyre is being driven in emergency conditions
⇒
.
End of emergency operation
Do not drive on if:
● smoke is coming from one of the tyres,
● there is a smell of rubber,
● the vehicle vibrates,
● there is a rattling noise.
When is it no longer possible to continue driving even using run-flat tyres?
● If one of the tyres has been severely damaged in an accident, etc. If a
tyre has been badly damaged there is a risk that parts of the tread can be
thrown off and cause damage to the fuel lines, brake pipes or fuel filler.
● It is also advisable to stop driving if severe vibrations occur, or if the
wheel starts overheating and gives off smoke.
1)
Depending upon version and country.
Safety FirstOperating InstructionsPractical TipsTechnical Specifications
246Wheels and tyres
Winter tyres
Winter tyres will improve the vehicles handling on snow and
ice.
In winter conditions winter tyres will considerably improve the vehicle's han-
dling. The design of summer tyres (width, rubber compound, tread pattern)
gives less grip on ice and snow.
Winter tyres must be inflated to a pressure 0.2 bar higher than the pres-
sures specified for summer tyres (see sticker on fuel tank flap).
Winter tyres must be fitted on all four wheels.
Information on permitted winter tyre sizes can be found in the vehicle's reg-
istration documentation. Use only radial winter tyres. All tyre sizes listed in
the vehicle documentation also apply to winter tyres.
Winter tyres lose their effectiveness when the tread is worn down to a depth
of 4 mm.
The speed rating code ⇒ page 244, New tyres and wheels determines the
following speed limits for winter tyres: ⇒
max. 160 km/h (100 mph)
max. 180 km/h (110 mph)
max. 190 km/h (120 mph)
max. 210 km/h (130 mph)
In some countries, vehicles which can exceed the speed rating of the fitted
tyre must have an appropriate sticker in the driver's field of view. These
stickers are available from your Technical Service. The legal requirements of
each country must be followed.
Do not have winter tyres fitted for unnecessarily long periods. Vehicles with
summer tyres handle better when the roads are free of snow and ice. Q
S
T
H If you have a flat tyre, please refer to the notes on the spare wheel
⇒ page 244, New tyres and wheels.
WARNING
The maximum speed for the winter tyres must not be exceeded. Other-
wise, this could lead to tyre damage and risk of accident.
For the sake of the environment
Fit your summer tyres again as soon as possible. They are quieter, do not
wear so quickly and reduce fuel consumption.
Snow chains
Snow chains may be fitted only to the front wheels, and only for 205/55R16
tyres. These tyres may only be fitted with fine-pitch link chains which do not
protrude more than 15 mm ⇒ page 244. For 225/50R17 tyres, the use of
snow chains is not permitted.
Remove wheel hub covers and trim rings before fitting snow chains. For
safety reasons cover caps, available in any Technical Service, must then be
fitted over the wheel bolts.
All-wheel drive : Where snow chains are compulsory on certain roads, this
normally also applies to cars with all-wheel drive. Snow chains may only be
fitted to the front wheels (also on vehicles with all-wheel drive).
WARNING
Snow chains should be correctly tightened in accordance with the manu-
facturer's instructions. This will prevent the chains coming into contact
with the wheel housing.
249
If and when
How to use the temporary spare wheel
Should you ever have a punctured tyre, the temporary spare wheel is only
intended for temporary use until you can reach a workshop. The standard-
size road wheel should be replaced as soon as possible.
Please note the following restrictions when using the temporary spare
wheel. This temporary spare wheel has been specially designed for your ve-
hicle, thus, it cannot be changed with the temporary spare wheel from an-
other vehicle.
No other type of tyre (normal summer or winter tyre) may be fitted on the
compact temporary spare wheel rim.
Snow chains
For technical reasons, snow chains must not be used on the compact tem-
porary spare wheel.
If you have a puncture on one of the front wheels when using snow chains,
fit the compact temporary spare wheel in place of one of the rear wheels.
You can then attach the snow chains to the wheel taken from the rear and
use this wheel to replace the punctured front wheel.
WARNING
● The tyre pressures must be checked and corrected as soon as possi-
ble after fitting the temporary spare wheel. The temporary spare wheel
pressure for dimensions 125/70R16 125/70R18 135/90R16 is 4.2 bar;
for all other tyre dimensions please refer to the label on the fuel cap. Fail-
ure to do so could result in an accident.
● Do not drive faster than 80 km/h (50 mph). Higher speeds can cause
an accident.
● Avoid heavy acceleration, hard braking and fast cornering. Risk of ac-
cident.
WARNING (Continued)
● Never use more than one temporary spare wheel at the same time,
risk of accident.
● No other type of tyre (normal summer or winter tyre) may be fitted on
the compact temporary spare wheel rim.
Tyre repair kit
The tyre repair kit (for vehicles not including a temporary
spare wheel) is stored under the floor panel in the luggage
compartment. In the event of a punctured tyre, your vehicle is equipped with the Tyre Mo-
bility System tyre repair kit.
The tyre repair kit consists of a container with sealing product to repair the
puncture and a compressor to generate the required tyre pressure. The kit
will reliably seal punctures up to a size of about 4 mm caused by the pene-
tration of a foreign body into the tyre.
Note
● Seek professional assistance if the repair of a tyre puncture is not possi-
ble with the sealing product.
Safety FirstOperating InstructionsPractical TipsTechnical Specifications
260If and when
Fuses on left side of dash panel
Fuses
NumberConsumerAmps1Vacant 2Vacant 3Vacant 4Vacant 5Vacant 6Vacant 7Vacant 8Vacant 9Airbag510RSE input (roof screen)1011Vacant 12Left xenon headlight10
13Instrument panel (oil level)/Switchboard wiring
(BCM)/Heater / ABS, ESC / Park Pilot/ Gateway/
Flow meter5
14Gearbox/ Power steering/ Brake light sensor/
Trailer/ ABS, ESC/ Haldex/ Light switch10
15Heated windscreen / Instrument lighting / Diag-
nosis switchboard/Engine management/Addi-
tional heating/AFS headlights/Park Pilot10
16Right xenon headlight1017Engine management1018Vacant 19Vacant
20Park Pilot (parking aid) / Gear lever/ ESC switch-
board10
21Vacant
NumberConsumerAmps22Volumetric alarm sensor/ Alarm horn523Diagnosis / Rain sensor / Light switch1024Trailer hook pre-installation assistant1525Vacant 26Vacuum pump2027RSE input (roof screen)1028Rear window wiper motor2029Vacant 30Cigarette lighter/power socket2031Vacant 32Vacant 33Heater4034Vacant 35Vacant 36Vacant 37Vacant 38Vacant 39Trailer control unit (coupling)15
40Trailer control unit (turn signals, brakes and left
side)20
41Trailer control unit (fog light, reverse light and
right side)20
42BCM wiring switchboard2043Trailer pre-installation4044Heated rear window2545Electric windows (front)3046Rear electric windows3047Engine (Fuel control unit, petrol relay)1548Convenience controls20
273
If and when
Starting
5. Start the engine of the vehicle with the boosting battery and let it run at idling speed.
6. Start the engine of the vehicle with the flat battery and wait two or three minutes until the engine is “running”.
Removing the jump leads
7. Before you remove the jump leads, switch off the dipped beam headlights (if they are switched on).
8. Turn on the heater blower and heated rear window in the vehi- cle with the flat battery. This helps minimise voltage peaks
which are generated when the leads are disconnected.
9. When the engine is running, disconnect the leads in reverse or- der to the details given above.
Connect the battery clamps so they have good metal-to-metal contact with
the battery terminals.
If the engine fails to start, switch off the starter after about 10 seconds and
try again after about half a minute.
WARNING
● Please note the safety warnings referring to working in the engine
compartment ⇒ page 222, Working in the engine compartment.
● The battery providing assistance must have the same voltage as the
flat battery (12V) and approximately the same capacity (see imprint on
battery). Failure to comply could result in an explosion.
WARNING (Continued)
● Never use jump leads when one of the batteries is frozen. Danger of
explosion! Even after the battery has thawed, battery acid could leak and
cause chemical burns. If a battery freezes, it should be replaced.
● Keep sparks, flames and lighted cigarettes away from batteries, dan-
ger of explosion. Failure to comply could result in an explosion.
● Observe the instructions provided by the manufacturer of the jump
leads.
● Do not connect the negative cable from the other vehicle directly to
the negative terminal of the flat battery. The gas emitted from the battery
could be ignited by sparks. Danger of explosion.
● Do not attach the negative cable from the other vehicle to parts of the
fuel system or to the brake line.
● The non-insulated parts of the battery clamps must not be allowed to
touch. The jump lead attached to the positive battery terminal must not
touch metal parts of the vehicle, this can cause a short circuit.
● Position the leads in such a way that they cannot come into contact
with any moving parts in the engine compartment.
● Do not lean on the batteries. This could result in chemical burns.
Note
The vehicles must not touch each other, otherwise electricity could flow as
soon as the positive terminals are connected.
Safety FirstOperating InstructionsPractical TipsTechnical Specifications
274If and when
Towing and tow-starting
Tow-starting
The use of jump leads is preferable to tow-starting.
We recommend that you do not tow-start your vehicle. Jump-start-
ing is preferable ⇒ page 271.
However, if your vehicle has to be tow-started:
– Engage the 2nd or the 3rd gear.
– Keep the clutch pressed down.
– Switch the ignition on.
– Once both vehicles are moving, release the clutch.
– As soon as the engine starts, press the clutch and move the
gear lever into neutral. This helps to prevent driving into the
towing vehicle.
WARNING
The risk of accidents is high when tow-starting. The vehicle being towed
can easily collide with the towing vehicle.
CAUTION
When tow-starting, fuel could enter the catalytic converter and damage it. General notes
Please observe the following points if you use a tow rope:
Notes for the driver of the towing vehicle
–
Drive slowly at first until the tow rope is taut. Then accelerate
gradually.
– Begin and change gears cautiously. If you are driving an auto-
matic vehicle, accelerate gently.
– Remember that the brake servo and power steering are not
working in the vehicle you are towing. Brake sooner than nor-
mal and pressing the pedal gently.
Notes for the driver of the towed vehicle
– Ensure that the tow rope remains taut at all times when towing.
Tow rope or tow bar
It is easier and safer to tow a vehicle with a tow bar. You should only use a
tow rope if you do not have a tow bar.
A tow rope should be slightly elastic to reduce the loading on both vehicles.
It is advisable to use a tow rope made of synthetic fibre or similarly elastic
material.
Attach the tow rope or the tow bar only to the towline anchorages provided
or a towing bracket.
Driving style
Towing requires some experience, especially when using a tow rope. Both
drivers should be familiar with the technique required for towing. Inexper-
ienced drivers should not attempt to tow.