2012 MERCEDES-BENZ C-Class COUPE brake

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. In most
cases, the tire pressure monitoring system
recognizes the new reference values
automatically.
However, you can also define reference
values manually as described here:
XSet the tire pressure ( Y page 297) to the
value recommended for the corresponding
driving situation on the Tire and Loading
Information placard on the driver's side
B-pillar.Additional tire pressure values for driving
at high speeds or with heavy loads can be
found in the tire pressure table on the
inside of the fuel filler flap.XMake sure that the tire pressure is correct
on all four wheels.XMake sure that the SmartKey is in position
2 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 multifunction display shows the
current tire pressure of the individual tires
or the Tire pressures will be
displayed after driving a few
minutes message.XPress the : button.
The Use Current Pressures as New
Reference Values message appears in
the multifunction display.
If you wish to confirm the restart:
XPress the a button.
The Tire Press. Monitor Restarted
message appears in the multifunction
display.
After driving for a few minutes, the system
checks whether the current tire pressures
are within the specified range. The new tire
pressures are then accepted as reference
values and monitored.
If you wish to cancel the restart:
XPress the % button.
The tire pressure values stored at the last
restart will continue to be monitored.Tire pressure305Wheels and tiresZ

Loading the vehicle
Instruction labels for tires and loads
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.
Two instruction labels on your vehicle show
the maximum possible load.
(1)The Tire and Loading Information placard
on the B-pillar on the driver's side. The
Tire and Loading Information placard
shows the maximum permissible number
of occupants and the maximum
permissible vehicle load. It also contains
details of the tire sizes and
corresponding pressures for tires
mounted at the factory.(2)The vehicle identification plate is on the
B-pillar on the driver's side. The vehicle
identification plate informs you of the
gross vehicle weight rating. It is made up
of the vehicle weight, all vehicle
occupants, the fuel and the cargo. You
can also find information about the
maximum gross axle weight rating on the
front and rear axle.
The maximum gross axle weight rating is
the maximum weight that can be carried
by one axle (front or rear axle). Never
exceed the maximum load or the
maximum gross axle weight rating for the
front or rear axle.:B-pillar, driver's side
Maximum permissible gross vehicle
weight rating
i The specifications shown on the Tire and
Loading Information placard in the
illustration are examples. The maximum
permissible gross vehicle weight rating is
vehicle-specific and may differ from that in
the illustration. You can find the valid
maximum permissible gross vehicle weight
rating for your vehicle on the Tire and
Loading Information placard.
XThe Tire and Loading Information placard
gives you details on maximum permissible
gross vehicle weight rating :: "The gross
weight of occupants and luggage must
never exceed XXX kilograms or XXX
pounds."
The gross weight of all vehicle occupants,
cargo, luggage and trailer load/noseweight (if
applicable) must not exceed the specified
value.
306Loading the vehicleWheels and tires

Example 1Example 2Example 3Step 3Permissible cargo
and trailer load/
noseweight
(maximum gross
vehicle weight rating
from the Tire and
Loading Information
placard minus the
gross weight of all
occupants)1500 lbs
(680 kg) -
750 lbs (340 kg)
= 750 lbs
(340 kg)1500 lbs
(680 kg) -
540 lbs (245 kg)
= 960 lbs
(435 kg)1500 lbs
(680 kg) -
150 lbs (68 kg) =
1350 lbs
(612 kg)
The higher the weight of all the occupants, the smaller the maximum load for luggage.
Further information can be found under "Towing a trailer" ( Y page 309).
Vehicle identification plate
Even if you have calculated the total load
carefully, you should still make sure that the
gross vehicle weight rating and the gross axle
weight rating are not exceeded. Details can
be found on the vehicle identification plate on
the B-pillar on the driver's side (Y page 306).
Gross vehicle weight: the gross weight of
the vehicle, all passengers, cargo and trailer
load/noseweight (if applicable) must not
exceed the permissible gross vehicle weight.
Gross axle weight rating: the maximum
permissible load that can be carried by one
axle (front or rear axle).
To ensure that your vehicle does not exceed
the maximum permissible values (gross
vehicle weight and maximum gross axle
weight rating), have your loaded vehicle
(including driver, occupants, cargo, and full
trailer load if applicable) weighed on a
suitable vehicle weighbridge.
Trailer load/noseweight
Your Mercedes-Benz has been designed
primarily to carry passengers and their
luggage. Mercedes-Benz does not
recommend towing a trailer with your vehicle.
Maximum load ratingGWARNING
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.
i The actual values for tires are specific to
each vehicle and may deviate from the
values in the illustration.
Maximum tire load : is the maximum
permitted weight for which the tire is
approved.
Maximum load rating309Wheels and tiresZ

Further information on tire loads
( Y page 311).
Uniform Tire Quality Grading
Standards
Overview of Tire Quality Grading
Standards
The Uniform Tire Quality Grading is a U.S.
Government requirement. Their purpose is to
provide drivers with consistent and reliable
information regarding tire performance. Tire
manufacturers are required to grade tires
using three performance factors: tread
wear :, tire traction ;, and temperature
resistance =. Although not a Government of
Canada requirement, all tires made for sale in
North America have these grades branded on
the sidewall.
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Where applicable, the tire grading
information can be found on the tire sidewall
between the tread shoulder and maximum
tire width.
For example:
Tread wearTractionTemperature200AAA
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. Government test course. For example, a
tire graded 150 would wear one and one-half
times as well on the government course as a
tire graded 100.
The relative performance of tires depends
upon the actual conditions of their use,
however, and may depart significantly from
the norm, due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
The traction grades, from highest to lowest,
are AA, A, B, and C. Those grades represent
the tire's ability to stop on a wet surface as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance.
GWARNING
If ice has formed on the road, tire traction will
be substantially reduced. Under such weather
conditions, drive, steer and brake with
extreme caution.
The safe speed on a wet, snow covered or icy
road is always lower than on dry road
surfaces.
You should pay special attention to road
conditions when temperatures are around
the freezing point.
Mercedes-Benz recommends a minimum tire
tread depth of 1
/ 6 in (4 mm) for all four winter
310Uniform Tire Quality Grading StandardsWheels and tires

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
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 309).
312Tire labelingWheels and tires

Maximum permissible tire pressure
Maximum permissible tire pressure for one
tire.
Maximum load on one tire
Maximum load on one tire. This is calculated
by dividing the maximum axle load of one axle
by two.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire
width in percent.
Tire pressure
This is pressure inside the tire applying an
outward force to each square inch of the tire's
surface. The tire pressure is specified in
pounds per square inch (psi), in kilopascal
(kPa) or in bar. The tire pressure should only
be corrected when the tires are cold.
Tire pressure of cold tires
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).
Tread
The part of the tire that comes into contact
with the road.
Bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim.
Sidewall
The part of the tire between the tread and the
bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
part and more than 2.3 kilograms (5 lbs).
These optional extras, such as high-
performance brakes, level control, a roof rack
or a high-performance battery, are not
included in the curb weight and accessory
weight.
TIN (Tire Identification Number)
This is a unique identifier which can be used
by a tire manufacturer to identify tires, for
example for a product recall, and thus identify
the purchasers. The TIN is made up of the
manufacturer's identity code, tire size, tire
type code and the manufacturing date.
Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of a tire.
Traction
Traction is the result of friction between the
tires and the road surface.
Definition of terms for tires and loading317Wheels and tiresZ

Treadwear indicators
Narrow bars (tread wear bars) that are
distributed over the tire tread. If the tire tread
is level with the bars, the wear limit of 1
/ 16 in
(1.6 mm) has been reached.
Occupant distribution
The distribution of occupants in a vehicle at
their designated seating positions.
Total load limit
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle's
designated seating capacity.
Changing a wheel
Flat tire
The "Breakdown assistance" section
( Y page 279) contains information and notes
on how to deal with a flat tire. It also provides
instructions on changing a wheel or mounting
the spare wheel/emergency spare wheel.
Interchanging the wheels
GWARNING
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs. rear),
tire rotation is not possible.
GWARNING
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
96 lb-ft (130 Nm).
Only use genuine Mercedes-Benz wheel bolts
specified for your vehicle's rims.
The wear patterns on the front and rear tires
differ, depending on the operating conditions.
Rotate the wheels before a clear wear pattern
has formed on the tires. Front tires typically
wear more on the shoulders and the rear tires
in the center.
If your vehicle's tire configuration allows, you
can rotate the wheels according to the
intervals in the tire manufacturer's warranty
book in your vehicle documents. If this is not
available, the tires should then be replaced
every 3000 to 6000 miles
( 5000 to 10,000 km), or earlier if the tire wear
requires this. Do not change the direction of
wheel rotation.
Clean the contact surfaces of the wheel and
the brake disc thoroughly every time a wheel
is interchanged. Check the tire pressures.
Information on changing a wheel and
mounting the spare wheel ( Y page 279).
! On vehicles equipped with a tire pressure
monitor, electronic components are
located in the wheel.
Tire-mounting tools should not be used
near the valve. This could damage the
electronic components.
Always have the tires changed at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
Direction of rotation
Tires with a specified direction of rotation
have additional benefits, e.g. if there is a risk
of hydroplaning. You will only gain these
benefits if the correct direction of rotation is
maintained.
An arrow on the sidewall of the tire indicates
its correct direction of rotation.
You may mount a spare wheel/emergency
spare wheel against the direction of rotation.
Observe the time restriction on use as well as
the speed limit specified on the spare wheel/
emergency spare wheel.
318Changing a wheelWheels and tires

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 23).
Notes on technical data
i The data stated here specifically refers to
a vehicle with standard equipment. Consult
an authorized Mercedes-Benz Center for
the data for all vehicle variants and trim
levels.
Genuine Mercedes-Benz parts
All Mercedes-Benz Centers maintain a supply
of genuine Mercedes-Benz parts for
necessary service and repair work. In
addition, strategically located parts delivery
centers provide for quick and reliable parts
service.
There are more than 300,000 different
genuine Mercedes-Benz parts available for
Mercedes-Benz models.
Genuine Mercedes-Benz parts are subject to
strict quality control. Each part has been
specially developed, manufactured or
selected for Mercedes-Benz vehicles and
fine-tuned for them.
Therefore, only genuine Mercedes-Benz parts
should be used.
GWARNING
Driving safety may be impaired if non-
approved parts, tires and wheels or safety-
relevant accessories are used.
This could lead to malfunctions in safety-
relevant systems, e.g. the brake system. This
could cause you to lose control of your vehicle
and cause an accident.
For this reason, Mercedes-Benz recommends
that you use genuine Mercedes-Benz parts or
parts of equal quality. Only use tires, wheels
and accessories that have been specifically
approved for your vehicle.
! Air bags and Emergency Tensioning
Devices, as well as control units and
sensors for these restraint systems may be
installed in the following areas of your
vehicle:
R doors
R door pillars
R door sills
R seats
R dashboard
R instrument cluster
R center console
Do not install accessories such as audio
systems in these areas. Do not carry out
repairs or welding. You could impair the
operating efficiency of the restraint
systems.
Have aftermarket accessories installed at
a qualified specialist workshop. Mercedes-
Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose.
HEnvironmental note
Daimler AG also supplies reconditioned major
assemblies and parts which are of the same
quality as new parts. They are covered by the
same Limited Warranty entitlements as new
parts.
Always specify the vehicle identification
number (VIN) ( Y page 325) and the engine
324Genuine Mercedes-Benz partsTechnical data