2012 MERCEDES-BENZ S-Class spare tire

Notes on regularly inspecting wheels
and tiresGWARNING
Regularly check the tires for damage.
Damaged tires can cause tire inflation
pressure loss. As a result, you could lose
control of your vehicle.
Worn, old tires can cause accidents. If the tire
tread is worn to minimum tread depth, or if
the tires have sustained damage, replace
them.
R Regularly check the wheels and tires of
your vehicle for damage (e.g. cuts,
punctures, tears, bulges on tires and
deformation or cracks or severe corrosion
on wheels) at least once a month, as well
as after driving off-road or on rough roads.
Damaged wheels can cause a loss of tire
pressure.
R Regularly check the tire tread depth and
the condition of the tread across the whole
width of the tire (Y page 491). If necessary,
turn the front wheels to full lock in order to
inspect the inner side of the tire surface.
R All wheels must have a valve cap to protect
the valve against dirt and moisture. Do not
mount anything onto the valve (such as tire
pressure monitoring systems) other than
the standard valve cap or other valve caps
approved by Mercedes-Benz for your
vehicle.
R Regularly check the pressure of all the tires
including the emergency spare wheel or the
spare wheel, particularly prior to long trips,
and correct the pressure as necessary
( Y page 493).
Tire tread
GWARNING
Although the applicable federal motor vehicle
safety laws consider a tire to be worn when
the tread wear indicators (TWI) become
visible at approximately 1
/ 16 in (1.6 mm), we
recommend that you do not allow your tires
to wear down to that level. As tread depth
approaches 1
/ 8 in (3 mm), the adhesion
properties on a wet road are sharply reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction varies
widely.
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).
Tread wear indicators (TWI) are required by
law. Six indicators are positioned on the tire
tread. They become visible as soon as a tread
depth of approximately 1
/ 16 inch (1.6 mm)
has been reached. If this is the case, the tire
is so worn that it must be replaced.
The recommended tread depth for summer
tires is at least 1
/ 8 inch (3 mm). The
recommended tread depth for winter tires is
at least 1
/ 6 inch (4 mm).
Bar marking
: for tread wear is integrated
into the tire tread.
Notes on selecting, mounting and
replacing tires
R Only mount tires and wheels of the same
type and make.
R Only mount tires of the correct size onto
the wheels.
R After mounting new tires, run them in at
moderate speeds for the first 60 miles
Operation491Wheels and tiresZ

(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 spare wheel/emergency 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.
You will find notes on driving with
MOExtended tires in the "Breakdown
assistance" section ( Y page 477).
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 513).
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.
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 497).XRestart the tire pressure monitor
( Y page 497).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
492Winter operationWheels and tires

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.
! You must drive at raised vehicle level if
snow chains have been mounted. The
vehicle could 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 mount snow chains on 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 71) 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,
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.
The recommended tire pressures for the tires
mounted at the factory can be found on the
labels described here.
Tire pressure493Wheels and tiresZ

If the tire pressures have been set to the
lower values for lighter loads and/or lower
road speeds, the pressures should be reset
to the higher values:
R if you want to drive with an increased load
and/or
R if you want to drive at higher road speeds.
i The tire pressures for increased loads
and/or higher road speeds, shown in the
tire pressure table, may have a negative
effect on driving comfort.
Option 3) The tire pressure for the
emergency/collapsible spare wheel
(depending on vehicle equipment) can be
found:
R printed in yellow on the rim of the
emergency/collapsible spare wheel
R in the "Wheel and tire combinations"
section ( Y page 514) in this manual
R on the Tire and Loading Information placard
on the B-pillar on the driver's side.
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.
Important notes on tire pressureGWARNING
Should the tire pressure drop repeatedly:
R check the tire for foreign bodies.
R check whether the wheel is losing air or the
valve is leaking.
R make sure that only a valve cap approved
by Mercedes-Benz is used on the tire valve.
Tire pressures that are too low have a
negative effect on vehicle safety, which could
lead you to cause an accident.
To test tire pressure, use a suitable tire
pressure gauge. The outer appearance of a
tire does not permit any reliable conclusion
about the tire pressure. On vehicles equipped
with the electronic tire pressure monitoring
system, the tire pressure can be checked
using the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is
dependent on the driving speed and the load.
Therefore, you should only correct tire
pressures when the tires are cold.
The tires are cold:
R if the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
R if the vehicle has not been driven more than
1 mile (1.6 km).
The tire temperature changes depending on
the outside temperature, the vehicle speed
and the tire load. If the tire temperature
changes by 18 ‡ (10 † ), the tire pressure
changes by approximately 10 kPa (0.1 bar/
1.5 psi). Take this into account when
checking the pressure of warm tires and only
correct the tire pressure if it is too low for the
current operating conditions. If you check the
tire pressure when the tires are warm, the
resulting value will be higher than if the tires
were cold. This is normal. Do not reduce the
tire pressure to the value specified for cold
tires. The tire pressure would otherwise be
too low.
Tire pressure495Wheels and tiresZ

Observe the recommended tire pressures for
cold tires
R on the Tire and Loading Information placard
on the B-pillar on the driver's side,
R in the tire pressure table on the inside of
the fuel filler flap,
R printed in yellow on the rim of the
emergency/collapsible spare wheel
(depending on vehicle equipment).
Underinflated or overinflated tires
Underinflated tires
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.
Underinflated tires can:
R wear excessively and/or unevenly
R adversely affect fuel economy
R fail from being overheated
R adversely affect handling
Overinflated tires
GWARNING
Follow recommended tire inflation pressures.
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.
Overinflated tires can:
R adversely affect handling
R wear excessively and/or unevenly
R be more likely to become damaged
Radversely affect ride comfort
R increase stopping distance
Maximum tire pressureGWARNING
Never exceed the maximum tire inflation
pressure. 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.
:Maximum permitted tire pressure
(example)
i The actual values for tires are specific to
each vehicle and may deviate from the
values in the illustration.
When adjusting the tire pressures always
observe the recommended tire pressure for
your vehicle ( Y page 493).
496Tire pressureWheels and tires

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 493).
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 493).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 monitor
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/malfunctions (USA)
or pressure loss (Canada). 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 USA only: 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.
Tire pressure497Wheels and tiresZ

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 303) in the ignition lock.XPress the = or ; button on the
steering wheel to select the Service
menu.XPress the 9 or : button to select
Tire Pressure .XPress the a button.
The current tire pressure for each wheel will
be displayed in the multifunction display.
If the vehicle has been parked for longer than
20 minutes, the Tire Pressures
Displayed After Driving A Few
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 Correct Tire Pressure message
appears in the multifunction display:
XCheck the tire pressure on all four wheels
and correct it if necessary.
i If the wheel positions on the vehicle are
interchanged, the tire pressures may be
displayed for the wrong positions for a
short time. This is rectified after a few
minutes of driving, and the tire pressures
are displayed for the correct positions.
Restarting the tire pressure monitor
GWARNING
It is the driver's responsibility to set the tire
pressure to the recommended cold tire
pressure. Underinflated tires affect the ability
to steer or brake the vehicle. You might lose
control over the vehicle.
When you restart the tire pressure monitor,
all existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tire pressures as the
reference values for monitoring.
The tire pressure monitor must be restarted
when you set the tire pressure to a new value
(as a result of changed drive or load
characteristics, for example). The tire
pressure monitor then monitors the new tire
pressure values.
i Canada only: in most cases, the tire
pressure monitor recognizes the new
reference values automatically. However,
Tire pressure499Wheels and tiresZ

CTire size designation, load-bearing
capacity and speed rating
( Y page 507)DLoad index ( Y page 509)ETire name
i
Tire data is vehicle-specific and may
deviate from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
:Tire width;Nominal aspect ratio in %=Tire code?Rim diameterALoad bearing indexBSpeed 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
Tire labeling507Wheels and tiresZ