2012 MERCEDES-BENZ B-CLASS tire pressure

Tire size designation, load-bearing
capacity and speed rating
:
Tire width
; Nominal aspect ratio in %
= Tire code
? Rim diameter
A Load bearing index
B 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 149mph (240km/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.
Do not overload the tires by exceeding the
specified load limit. The maximum
permissible load can be found on the
vehicle's Tire and Loading Information
placard on the B-pillar on the driver's side
(Y page 306).
Example:
A load-bearing index of 91 indicates a
maximum load of 1,356lb (615kg) that can be
carried by the tires. For further information on
the maximum tire load in kilograms and
pounds, see (Y page 310).
For further information on the load-bearing
index, see Load index ( Y page 315).
Speed rating: speed rating B specifies the
approved maximum speed of the tire. G
WARNING
Exceeding the stated tire load-bearing
capacity and the approved maximum speed
could lead to

tire damage or the tire bursting.
There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.
Regardless of the speed rating, always
observe the speed limits. Drive carefully and Tire labeling
313
Wheels and tires Z
ProCarManuals.com

Load index
In addition to the load bearing index, load
index : may be imprinted after the letters
that identify speed index B(Y page 313) on
the sidewall of the tire.
R
If no
specification
is given: no text (as in the
example above), represents a standard
load (SL) tire
R XL or Extra Load: represents a reinforced
tire
R Light Load: represents a light load tire
R C, D, E: represents a load range that
depends on the maximum load that the tire
can carry at a certain pressure
i Tire data is vehicle-specific and may
deviate from the data in the example. DOT, Tire Identification Number (TIN)
Canadian tire regulations prescribe that every
new tire manufacturer or retreader has to
imprint a
TIN

in or on the sidewall of each tire
produced. The TIN is a unique identification number. The
TIN makes it easier for tire manufacturers or
retreaders to notify customers of recalls or
other safety-related matters. It makes it
possible for the purchaser to easily identify
the affected tires.
The TIN consists of the manufacturer
identification code ;, tire size =, tire type
code ? and manufacturing date A.
DOT (Department of Transportation):
tire
symbol : indicates that the tire complies
with the requirements of the Canadian
Transport Ministry.
Manufacturer identification code:
manufacturer identification code
;

provides
details on the tire manufacturer. New tires
have a code with two symbols. Retreaded
tires have a code with four symbols.
Further information about retreaded tires
(Y page 298).
Tire size: identifier = describes the tire size.
Tire type code: tire type code ? can be
used by the manufacturer as a code to
describe specific characteristics of the tire.
Date of manufacture: date of manufacture
A provides information about the age of a
tire. The first and second positions represent
the week of manufacture, starting with "01"
for the first calendar week. Positions three
and four represent the year of manufacture.
For example, a tire that is marked with
"3208", was manufactured in week 32 in
2008.
i Tire data is vehicle-specific and may
deviate from the data in the example. Tire labeling
315
Wheels and tires Z
ProCarManuals.com

Tire characteristics
This information describes the tire cord and
the number
of
layers in sidewall : and under
tire tread ;.
i Tire data is vehicle-specific and may
deviate from the data in the example. Definition of terms for tires and
loading
Tire ply composition and material
used
Describes the number

of plies or the number
of layers of rubber-coated fabric in the tire
tread and sidewall. These are made of steel,
nylon, polyester and other materials. Bar
Metric unit for tire pressure.
14.5038 pounds per square inch (psi) and 100 kilopascals (kPa) are the equivalent of
1 bar. DOT (Department of Transportation)
DOT marked tires fulfill the requirements of
the Canadian Transport Ministry. Normal occupant weight
The number of occupants for which the
vehicle is designed multiplied by
68 kilograms (150 lb). Uniform Tire Quality Grading
Standards
A uniform standard to grade the quality of
tires with regards

to tread quality, tire traction
and temperature characteristics. Ratings are
determined by tire manufacturers using U.S.
government testing procedures. The ratings
are molded into the sidewall of the tire. Recommended tire pressure
The recommended tire pressure applies to
the tires mounted at the factory.
The Tire and Loading Information placard
contains the recommended

tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissible vehicle speed.
The tire pressure table contains the
recommended pressures for cold tires for
various operating conditions, i.e. differing
load and speed conditions. Increased vehicle weight due to
optional equipment
This is the combined weight of all standard
and optional equipment available for the
vehicle, regardless of whether it is actually
installed on the vehicle or not. Rim
This is the

part of the wheel on which the tire
is mounted. 316
Definition of terms for tires and loading
Wheels and tires
ProCarManuals.com

GAWR (Gross Axle Weight Rating)
The GAWR is
the maximum gross axle weight
rating. 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. Speed rating
The speed rating is part of the tire
identification. It specifies

the speed range for
which the tire is approved. GVW (Gross Vehicle Weight)
The gross vehicle weight includes 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:
R the curb weight of the vehicle
R the weight of the accessories
R the load limit
R the weight of the factory installed optional
equipment Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa
corresponds to 1 psi. Another unit for tire
pressure is bar. 100 kilopascal (kPa) is the
equivalent of 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. 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. Definition of terms for tires and loading
317
Wheels and tires Z
ProCarManuals.com

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 further
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 kg (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 the weight of the
accessories.
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. 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 á in
(1.6 mm) has been reached. Occupant distribution
The distribution of occupants in a vehicle at
their designated seating positions. Total load limit
Nominal load and luggage load plus
68 kilograms (150 lb) multiplied by the
number of seats in the vehicle. 318
Definition of terms for tires and loading
Wheels and tires
ProCarManuals.com

Changing a wheel
Flat tire
You can find
information on what to do in the
event of a flat tire in the "Flat tire" section
(Y page 281). You will also find information
on driving with MOExtended tires in the event
of a flat tire.
Vehicle with emergency spare wheel: in
the event of a flat tire, the emergency spare
wheel is mounted as described under
"Mounting a wheel" ( Y page 319).Rotating the wheels
G
WARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or

tires have different dimensions.
The wheel brakes or suspension components
may also be damaged. There is a risk of
accident.
Rotate front and rear wheels only if the wheels
and tires are of the same dimensions.
Always pay attention to the instructions and
safety notes when changing a wheel
(Y page 319).
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 no
warranty book is available, the tires should be
interchanged every 3,000 to 6,000 miles
(5,000 to 10,000 km), or earlier if tire wear
requires. 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 pressure and, if necessary, restart the tire pressure loss
warning system.
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. Storing wheels
Store wheels that

are not being used in a cool,
dry and preferably dark place. Protect the
tires from oil, grease, gasoline and diesel. Cleaning the wheels
G
WARNING
The water jet from a circular jet nozzle (dirt
blasters) can cause

invisible exterior damage
to the tires or chassis components.
Components damaged in this way may fail
unexpectedly. There is a risk of an accident.
Do not use power washers with circular jet
nozzles to clean the vehicle. Have damaged
tires or chassis components replaced
immediately. Mounting a wheel
Preparing the vehicle X
Stop the vehicle on solid, non-slippery and
level ground.
X Apply the electric parking brake manually
(Y page 150).
X Bring the front wheels into the straight-
ahead position.
X Move the DIRECT SELECT lever to position
P. Changing a wheel
319
Wheels and tires Z
ProCarManuals.com

X
Place the ratchet wrench onto the hexagon
nut of the jack so that the letters AB are
visible.
X Turn the ratchet wrench until the vehicle is
once again standing firmly on the ground.
X Place the jack to one side.
X Tighten the wheel bolts evenly in a
crosswise pattern in the sequence
indicated ( : to A).
The tightening torque
must be 96 lb-ft (130 Nm).
X Turn the jack back to its initial position.
X Stow the jack and the rest of the vehicle
tools in the vehicle again.
X Check the tire pressure of the newly
mounted wheel and adjust it if necessary.
Observe the recommended tire pressure
(Y page 301). Wheel and tire combinations
General notes
! For safety reasons, Mercedes-Benz
recommends that you only use tires and
wheels which have been approved by
Mercedes-Benz specifically for your
vehicle.
These tires have

been specially adapted for
use with the control systems, such as ABS
or ESP ®
, and are marked as follows:
R MO = Mercedes-Benz Original
R MOE = Mercedes-Benz Original Extended
(tires featuring run-flat characteristics)
R MO1 = Mercedes-Benz Original (only
certain AMG tires)
Mercedes-Benz Original Extended tires
may only be used on wheels that have been
specifically approved by Mercedes-Benz.
Only use tires, wheels or accessories
tested and approved by Mercedes-Benz.
Certain characteristics, e.g. handling,
vehicle noise emissions or fuel
consumption, may otherwise be adversely
affected. In addition, when driving with a load, tire dimension variations could cause
the tires to come into contact with the
bodywork
and axle

components. This could
result in damage to the tires or the vehicle.
Mercedes-Benz accepts no liability for
damage resulting from the use of tires,
wheels or accessories other than those
tested and approved.
Information on tires, wheels and approved
combinations can be obtained from any
qualified specialist workshop.
! Retreaded tires are neither tested nor
recommended by Mercedes-Benz, since
previous damage cannot always be
detected on retreaded tires. As a result,
Mercedes-Benz cannot guarantee vehicle
safety if retreaded tires are mounted. Do
not mount used tires if you have no
information about their previous usage.
Overview of abbreviations used in the
following tire tables:
R BA: both axles
R FA: front axle
R RA: rear axle
The recommended pressures for various
operating conditions can be found:
R on the Tire and Loading Information placard
with the recommended tire pressures on
the B-pillar on the driver's side
R in the tire pressure table on the inside of
the fuel filler flap
Observe the notes on recommended tire
pressures under various operating conditions
(Y page 301).
Check tire pressures regularly, and only when
the tires are cold. Comply with the
maintenance recommendations of the tire
manufacturer in the vehicle document wallet. Wheel and tire combinations
323
Wheels and tires Z
ProCarManuals.com

Tires
Summer tires Alloy wheels V1
BA
225/40 R18 92 W XL MOExtended
8, 9 7.5 J x 18 H2
Wheel offset: 2.05 in (52 mm) #
All-weather tires Alloy wheels V1
BA
225/45 R17 91 H M+SMOExtended
8, 9 7.5 J x 17 H2
Wheel offset: 2.07 in (52.5 mm
) #
Winter tires Alloy wheels V1
BA 205/50 R17 93 H XL M+S
i 6.5 J x 17 H2
Wheel offset: 1.93 in (49 mm) #
BA 205/50 R17 93 H XL
M+SiMOExtended
9 6.5 J x 17 H2
Wheel offset: 1.93 in (49 mm) #
Emergency spare wheel
Important safety notes
G
WARNING
The wheel or tire size as well as the tire type
of the spare
wheel or emergency spare wheel
and the wheel to be replaced may differ.
Mounting an emergency spare wheel may
severely impair the driving characteristics.
There is a risk of an accident.
To avoid hazardous situations:
R adapt your driving style accordingly and
drive carefully.
R never mount more than one spare wheel or
emergency spare wheel that differs in size.
R only use a spare wheel or emergency spare
wheel of a different size briefly.
R do not switch ESP ®
off.
R have a spare wheel or emergency spare
wheel of a different size replaced at the
nearest qualified specialist workshop. Observe that the wheel and tire dimensions
as well as the tire type must be correct.
When using an emergency spare wheel or
spare wheel of a different size, you must not
exceed the maximum speed of 50 mph
(80 km/h).
Snow chains must not be mounted on
emergency spare wheels. General notes
You should regularly check the pressure of
the emergency spare

wheel, particularly prior
to long trips, and correct the pressure as
necessary ( Y page 301). The value on the
wheel or as given in the "Technical data"
section ( Y page 323) is valid.
i When you are driving with the emergency
spare wheel mounted, the tire pressure
loss warning system cannot function
reliably. Only restart the tire pressure loss
8 Use of snow chains is not permitted. Observe the notes in the "Snow chains" section.
9 MOExtended tires (tires with run-flat characteristics) only in conjunction with activated tire pressure loss
warning. Emergency spare wheel
325
Wheels and tires Z
ProCarManuals.com