2012 MERCEDES-BENZ R-Class spare wheel

(100 km) as they only reach their full
performance after this distance.
R Do not use tires that are excessively worn
as the tire traction on wet road surfaces
decreases significantly when the tread
depth is less than 1
/ 8 inch (3 mm).
R Replace the tires after six years at the
latest, regardless of wear. This also applies
to the emergency spare wheel/spare
wheel.
The service life of tires depends on the
following factors amongst other things:
R driving style
R tire pressure
R mileage
MOExtended tires (tires with run-flat
properties)
MOExtended tires (tires with run-flat
properties) allow you to continue driving your
vehicle even if one or more tires are entirely
deflated.
MOExtended tires may be used only in
conjunction with the activated tire pressure
loss warning system or the activated tire
pressure monitoring system and only on
wheels specifically tested by Mercedes-Benz.
i Vehicles equipped with MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from an
authorized Mercedes-Benz Center.
You will find notes on driving with a flat tire in
the "Breakdown assistance" section
( Y page 309).
Winter operation
Please bear the following in mind
At the onset of winter, have your vehicle
winterproofed at a qualified specialist
workshop, e.g. at an authorized Mercedes-
Benz Center.
Observe the notes in the "Changing a wheel"
section ( Y page 346).
Driving with summer tires
At temperatures below 45 ‡ (+7 †), the
elasticity of summer tires and therefore also
traction and braking capability are reduced
considerably — equip your vehicle with
M+S tires. Using summer tires at very cold
temperatures could cause tears to form,
thereby damaging the tires permanently.
Mercedes-Benz cannot accept responsibility
for this type of damage.
M+S tires
At temperatures below 45 ‡(+7 †), use
winter tires or all-season tires. Both types of
tire are identified by the M+S marking.
Only winter tires bearing the i snowflake
symbol in addition to the M+S marking
provide the best possible grip in wintry road
conditions. Only these tires will allow driving
safety systems such as ABS and ESP ®
to
function optimally in winter, as these tires
have been designed specifically for driving on
snow.
Use M+S tires of the same make and tread on
all wheels to maintain safe handling
characteristics.
GWARNING
M+S tires with a tread depth of less than 1
/ 6
inch (4 mm) must be replaced immediately.
They are no longer suitable for use in winter.
324Winter operationWheels and tires

Always observe the maximum permissible
speed specified for the M+S tires you have
mounted.
Once you have mounted the winter tires:XCheck the tire pressures ( Y page 329).XRestart the tire pressure monitor
( Y page 331).GWARNING
If you use your spare wheel when M+S tires
are mounted on the other wheels, be aware
that the difference in tire characteristics
impairs cornering ability and reduces driving
stability. Adapt your driving style accordingly.
Have the spare wheel replaced by a normal
wheel with an M+S tire at the nearest
Mercedes-Benz Center.
Snow chains
For safety reasons, Mercedes-Benz
recommends that you only use snow chains
which have been specially approved for your
vehicle by Mercedes-Benz, or are of a
corresponding standard of quality.
! Vehicles with the Adaptive Damping
System (ADS): do not drive in ADS SPORT
mode if snow chains have been mounted.
The vehicle may otherwise be damaged.
! There is not enough space for snow
chains on some wheel sizes. Observe the
information under "Tires and wheels" in the
"Technical Data" section to avoid damage
to the vehicle or the wheels.
R Only use snow chains when driving on
roads completely covered by snow. Do not
exceed the maximum permissible speed of
30 mph (50 km/h). Remove the snow
chains as soon as possible when you are no
longer driving on snow-covered roads.
R Local regulations may restrict the use of
snow chains. Applicable regulations must
be observed if you wish to mount snow
chains.
R Snow chains must not be mounted on
emergency spare wheels.
If you intend to mount snow chains, please
bear the following points in mind:
R you may not attach snow chains to all
wheel-tire combinations; see the
information under "Wheel and tire
combinations" in the "Wheels and tires"
section.
R mount snow chains only in pairs and only
to the rear wheels. Observe the
manufacturer's installation instructions.
! If snow chains are mounted on the front
wheels, the snow chains could grind
against the bodywork or components of the
chassis. This could result in damage to the
vehicle or the tires.
! Vehicles with steel wheels: if you wish
to install snow chains to steel wheels, make
sure that you remove the respective
wheels' hubcaps first. The hubcaps may
otherwise be damaged.
i You may wish to deactivate
ESP ®
(Y page 66) when pulling away with
snow chains mounted. This way you can
allow the wheels to spin in a controlled
manner, achieving an increased driving
force (cutting action).
Tire pressure
Tire pressure specifications
GWARNING
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
Tire pressure325Wheels and tiresZ

Important notes on tire pressureGWARNING
If the tire pressure drops repeatedly, check
the tires for punctures from foreign objects
and/or whether air is leaking from the valves
or from around the rim.
The tire temperature and pressure increase
when the vehicle is in motion. This is
dependent on the driving speed and the load.
If you wish to drive at high speeds of
100 mph (160 km/h) or higher when this is
allowed, use the tire pressure table on the
inside of the fuel filler flap to set the correct
tire pressures when the tires are cold. If the
tire pressure is not set correctly, this can lead
to an excessive build up of heat and a sudden
loss of pressure.
For further information, consult a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
i Driving comfort can be impaired if the tire
pressure value recommended in the tire
pressure table for speeds over
100 mph(160 km/h) is adopted.
Make sure that the tire pressure for normal
speeds is adopted again.
Additional specifications of tire pressure
values for loads can also be found on the tire
pressure table on the inside of the fuel filler
flap.
The tire pressure for emergency spare wheels
can be found:
R printed in yellow on the rim of the
emergency spare wheel
R in the "Wheel and tire combinations"
section ( Y page 347) in this manual
R on the Tire and Loading Information placard
on the B-pillar on the driver's side.
i Specifications shown in the examples of
tire pressure tables are for illustration
purposes only. Tire pressure specifications
are vehicle-specific and may deviate from
the data shown here. Tire pressure
specifications applicable to your vehicle
are located in your vehicle's tire pressure
table.
Unless stated otherwise, the tire pressures
specified on the fuel filler flap apply for all
tires approved for this vehicle.
Tire pressure table for all tires permitted for this
vehicle by the factory (example)
If a tire size precedes a tire pressure, the tire
pressure information following is only valid
for that tire size. The load conditions "partially
laden" and "fully laden" are defined in the
table for different numbers of passengers and
amounts of luggage. The actual number of
seats may differ.
Tire pressure table with tire dimensions (example)
Some tire pressure tables show only the rim
diameters instead of the full tire size, e.g.
R18 . The rim diameter is part of the tire
dimension and can be found on the sidewall
of the tire ( Y page 340).
Tire pressure327Wheels and tiresZ

Checking the tire pressures
Important safety notesGWARNING
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
Check the tire pressure at least once a month.
Only check and correct tire pressures when
the tires are cold ( Y page 325).
Checking tire pressure manually
To determine and set the correct tire
pressure, proceed as follows:
XRemove the valve cap of the tire that is to
be checked.XPress the tire pressure gauge securely onto
the valve.XRead the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard on the
B-pillar on the driver's side of your vehicle.XIf necessary, increase the tire pressure to
the recommended value ( Y page 325).XIf the tire pressure is too high, release air
by pressing down the metal pin in the valve
using the tip of a pen, for example. Thencheck the tire pressure again using the tire
pressure gauge.XScrew the valve cap onto the valve.XRepeat these steps for the other tires.
Tire pressure loss warning system
(Canada only)
Important safety notes
While the vehicle is in motion, the tire
pressure loss warning system monitors the
set tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss in a tire. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appear in the multifunction
display.
GWARNING
When the multifunction display shows the
message Tire Pressure Check Tires , one
or more of your tires are significantly
underinflated. You should stop and check
your tires as soon as possible, and inflate
them to the proper tire inflation pressure as
indicated on the vehicle's Tire and Loading
Information placard or on the tire inflation
pressure label.
Driving on a significantly underinflated tire
causes the tire to overheat and can lead to
tire failure. Underinflation also reduces fuel
efficiency and tire tread life, and may affect
the vehicle's handling and stopping ability.
Each tire, including the spare, should be
checked at least once a month when cold.
Inflate the tires to the recommended tire
inflation pressure as specified on
R the Tire and Loading Information placard on
the driver's door B-pillar
or
R the tire inflation pressure label located on
the inside of the fuel filler flap
Tire pressure329Wheels and tiresZ

If you wish to cancel the restart:XPress the X button.
or
XWait until the Restart Run Flat
Indicator? message goes out.
The tire pressure values stored at the last
restart will continue to be monitored.
Tire pressure monitor (USA only)
Important safety notes
If a tire pressure monitor system is installed,
the vehicle's wheels have sensors that
monitor the tire pressures in all four tires. The
tire pressure monitor warns you when the
pressure drops in one or more of the tires. The
tire pressure monitor only functions if the
correct wheel electronics units are installed
on all wheels.
The tire pressure monitor has a yellow
warning lamp in the instrument cluster for
indicating pressure loss or a malfunction.
Whether the warning lamp flashes or lights up
indicates whether a tire pressure is too low or
the tire pressure monitoring system is
malfunctioning:
R if the warning lamp is lit continuously, the
tire pressure on one or more tires is
significantly too low. The tire pressure
monitor is not malfunctioning.
R if the warning lamp flashes for 60 seconds
and then remains lit constantly, the tire
pressure monitor is malfunctioning.
GWARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure
recommended by the vehicle manufacturer
on the tire and Loading Information placard
on the driver's door B-pillar or the tire
pressure label on the inside of the fuel filler
flap. If your vehicle has tires of a different size
than the size indicated on the tire and Loading
Information placard or the tire pressure label,
you should determine the proper tire pressure
for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires are significantly underinflated.
Accordingly, when the low tire pressure
telltale illuminates, you should stop and check
your tires as soon as possible, and inflate
them to the proper pressure. Driving on a
significantly underinflated tire causes the tire
to overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's
handling and stopping ability.
Please note that the TPMS is not a substitute
for proper tire maintenance, and it is the
driver's responsibility to maintain correct tire
pressure, even if underinflation has not
reached the level to trigger illumination of the
TPMS low tire pressure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined with
the low tire pressure telltale. When the
system detects a malfunction, the telltale will
flash for approximately one minute and then
remain continuously illuminated. This
sequence will be repeated every time the
vehicle is started as long as the malfunction
exists.
When the malfunction indicator is illuminated,
the system may not be able to detect or signal
low tire pressure as intended. TPMS
malfunctions may occur for a variety of
reasons, including the mounting of
incompatible replacement or alternate tires
or wheels on the vehicle that prevent the
TPMS from functioning properly. Always
check the TPMS malfunction telltale after
replacing one or more tires or wheels on your
vehicle to ensure that the replacement or
alternate tires and wheels allow the TPMS to
continue to function properly.Tire pressure331Wheels and tiresZ

iIf the tire pressure monitor is
malfunctioning, it may take more than
10 minutes for the tire pressure warning
lamp to inform you of the malfunction by
flashing for 60 seconds and then remaining
lit.
When the malfunction has been rectified,
the tire pressure warning lamp goes out
after driving for a few minutes.
Information on tire pressures is displayed in
the multifunction display. After a few minutes
of driving, the current tire pressure of each
tire is shown in the multifunction display.
i The tire pressure values indicated by the
on-board computer may differ from those
measured at a gas station with a pressure
gauge. The tire pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tire pressure
values indicated by a pressure gauge are
higher than those shown by the on-board
computer. In this case, do not reduce the
tire pressures.
i The operation of the tire pressure monitor
can be affected by interference from radio
transmitting equipment (e.g. radio
headphones, two-way radios) that may be
being operated in or near the vehicle.
i This device complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.Checking tire pressure electronicallyXMake sure that the SmartKey is in position
2 (Y page 145) in the ignition lock.XPress and hold the V or U button on
the multifunction steering wheel until the
standard display appears in the
multifunction display ( Y page 202).XPress and hold the & or * button
until the current tire pressure of each tire
is shown in the multifunction display.
If the vehicle has been parked for longer than
20 minutes, the Tire pressure
displayed after driving for several
minutes message appears in the display.
After a teach-in period, the tire pressure
monitor automatically recognizes new wheels
or new sensors. If a clear allocation of the tire
pressure values to the individual wheels is not
possible, the Tire Pressure Monitor
Active message is shown instead of the tire
pressure display. The tire pressures are
already being monitored.
i If a spare wheel/emergency spare wheel
is mounted, the system may continue to
show the tire pressure of the wheel that has
been removed for a few minutes. If this
occurs, note that the value displayed for
the position where the spare tire is
mounted is not the same as the spare
wheel/emergency spare wheel's current
tire pressure.
Tire pressure monitor warning
messages
If the tire pressure monitor detects a
significant pressure loss on one or more tires,
a warning message is shown in the
multifunction display. A warning tone also
sounds and the tire pressure warning lamp
lights up in the instrument cluster.
Each tire that is affected by a significant loss
of pressure is highlighted with a color.
If the Tire Pressure(s) Please Correct
[bar] message appears in the multifunction
display:
332Tire pressureWheels and tires

Tire size designation, load-bearing
capacity and speed index:Tire width;Nominal aspect ratio in %=Tire code?Rim diameterALoad bearing indexBTire speed rating
i Tire data is vehicle-specific and may
deviate from the data in the example.
General: depending on the manufacturer's
standards, the size imprinted in the tire wall
may not contain any letters or may contain
one letter that precedes the size description.
If there is no letter preceding the size
description (as shown above): these are
passenger vehicle tires according to
European manufacturing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S.
manufacturing standards.
If "LT" precedes the size description: these
are light truck tires according to U.S.
manufacturing standards.
If "T" precedes the size description: these are
compact emergency spare wheels at high tire
pressure, to be used only temporarily in an
emergency.
Tire width: tire width : shows the nominal
tire width in millimeters.
Nominal aspect ratio: aspect ratio ; is the
size ratio between the tire height and the tire
width and is shown in percent. The aspect
ratio is calculated by dividing the tire width by
the tire height.
Tire code: tire code = specifies the tire type.
"R" represents radial tires. "D" represents
diagonal tires, "B" represents diagonal radial
tires.
Optionally, tires with a maximum speed of
over 149 mph(240 km/h) may have "ZR" in
the size description depending on the
manufacturer (e.g. 245/40 ZR 18).
Rim diameter: rim diameter ? is the
diameter of the bead seat, not the diameter
of the rim flange. The rim diameter is
specified in inches (in).
Load bearing index: load bearing index A
is a numerical code which specifies the
maximum load-bearing capacity of a tire.GWARNING
The tire load rating must always be at least
half of the GAWR of your vehicle. Otherwise,
sudden tire failure may be the result which
could cause an accident and/or serious injury
to you or others.
Always replace rims and tires with rims and
tires having the same specifications
(designation, manufacturer and type) as
shown on the original part.
GWARNING
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
Example:
The load bearing index 91 is equivalent to a
maximum load of 1356 lbs (615 kg) that the
tire can carry. For further information on the
maximum tire load in kilograms and pounds,
see ( Y page 337).
340Tire labelingWheels and tires

Rim
This is the part of the wheel on which the tire
is mounted.
GAWR (Gross Axle Weight Rating)
The GAWR is the maximum permissible axle
weight. The actual load on an axle must never
exceed the gross axle weight rating. The
gross axle weight rating can be found on the
vehicle identification plate on the B-pillar on
the driver's side.
Tire speed rating
The tire speed rating is part of the tire
identification. It specifies the speed range for
which the tire is approved.
GTW (Gross Trailer Weight)
The GTW is the weight of a trailer including
the weight of the load, luggage, accessories
etc. on the trailer.
GVW (Gross Vehicle Weight)
The gross vehicle weight comprises the
weight of the vehicle including fuel, tools, the
spare wheel, accessories installed,
occupants, luggage and the drawbar
noseweight if applicable. The gross vehicle
weight must not exceed the gross vehicle
weight rating GVWR as specified on the
vehicle identification plate on the B pillar on
the driver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible gross
weight of a fully loaded vehicle (the weight of
the vehicle including all accessories,
occupants, fuel, luggage and the drawbar
noseweight if applicable). The gross vehicle
weight rating is specified on the vehicle
identification plate on the B-pillar on the
driver's side.
Maximum loaded vehicle weight
The maximum weight is the sum of the curb
weight of the vehicle, the weight of the
accessories, the total load limit and the
weight of the optional equipment installed at
the factory.
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa is the
equivalent of 1 psi. Another unit for tire
pressure is bar. There are 100 kilopascals
(kPa) to 1 bar.
Load index
In addition to the load bearing index, the load
index may also be imprinted on the sidewall
of the tire. This specifies the load bearing
capacity more precisely.
Curb weight
The weight of a vehicle with standard
equipment including the maximum capacity
of fuel, oil and coolant. It also includes the air-
conditioning system and optional equipment
if these are installed in the vehicle, but does
not include passengers or luggage.
Maximum load rating
The maximum load rating in kilograms or
pounds is the maximum weight for which a
tire is approved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one
tire.
344Definition of terms for tires and loadingWheels and tires