Page 377 of 410

RWeight of the occupants
-Occupant 1: 200 lbs (91 kg)
-Occupant 2: 190 lbs (86 kg)
-Occupant 3: 150 lbs (68 kg)
RTotal weight of all occupants: 540 lbs (245 kg)
Step 3
RPermissible load (maximum gross vehicle weight rating from the Tire and Loading Informa-
tion placard minus the gross weight of all occupants):
1500 lbs (680 kg) Ò540 lbs (245 kg) =960 lbs (435 kg)
Example 3
Step 1
RCombined maximum weight of occupants and load (data from the Tire and Loading Infor-
mation placard): 1500 lbs (680 kg)
Step 2
RNumber of people in the vehicle (driver and occupants): 2
RDistribution of the occupants:
-Front: 1
RWeight of the occupants
-Occupant 1: 150 lbs (68 kg)
RTotal weight of all occupants: 150 lbs (68 kg)
Step 3
RPermissible load (maximum gross vehicle weight rating from the Tire and Loading Informa- tion placard minus the gross weight of all occupants):
1500 lbs (680 kg) Ò150 lbs (68 kg) = 1350 lbs (612 kg)
Vehicle identification plate
Even if you have calculated the total cargo
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 of the vehicle
(
Ypage 372).
Permissible Gross Vehicle Weight Rating
(GVWR): the gross weight of the vehicle, all
passengers, load and trailer load/noseweight
(if applicable) must not exceed the permissi-
ble gross vehicle weight.
Gross Axle Weight Rating (GAWR): the
maximum permissible weight that can be car-
ried by one axle (front or rear axle). To ensure that your vehicle does not exceed
the maximum permissible values (gross vehi-
cle 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.
Loading the vehicle375
Wheels and tires
Z
Page 378 of 410

All about wheels and tires
UniformTire Quality Grading Stand-
ards
Overview ofTire Quality Grading Stand-
ards
Uniform Tir eQuality Grading Standards are
U.S. governmen tspecifications. Their pur-
pos eis to provide drivers wit hunifor mrelia-
ble information on tire performance data. Tir e
manufacturers hav eto grad etires usin gthree
performance factors :: tread wear grade, ;
traction grad eand =temperature grade.
These regulation sdo no tapply to Canada.
Nevertheless, all tires sold in North America
are provide dwit hth ecorresponding qualit y
grading marking son th esidewall of th etire.
Quality grades can be found, wher eapplica-
ble, on th etire sidewall between th etread
shoulder and maximum tire width.
Example:
RTreadwear grade: 200
RTraction grade: AA
RTemperaturegrade: A
Al lpassenger car tires mus tconform to th e
statutory safet yrequirements in addition to
these grades.
iThe actual value sfor tires are vehicle-
specific and may deviat efrom th evalue sin
th eillustration .
Treadwear
The treadwea rgrad eis acomparative rating
base don th ewear rat eof th etire when te sted
under controlled condition son aspecifie d
U.S. governmen tcourse. Fo rexample, atire
graded 15 0would wear on eand one-half
times as well on th egovernmen tcours eas a
tire graded 100.
The relative performance of tires depend s
upon th eactual condition sof their use, how-
ever, and may depar tsignificantly from th e
norm due to variation sin driving habit s, ser-
vic epractice sand difference sin road char-
acteri stics and climat econditions.
Traction
GWARNIN G
The traction grad eassigned to this tire is
base don straight-ahead braking traction
tests, and does no tinclude acceleration ,cor-
nering, hydroplaning ,or peak traction char-
acteristics .
!Avoid wheelspin .This can lead to damag e
to th edriv etrain .
The traction grades –from highest to lowes t –
are AA ,A, Band C. Those grades represen t
th etire' sabilit yto stop on wet pavemen tas
measured under controlled condition son
specifie dgovernmen tte st surfaces of asphalt
and concrete. Atire marke d Cmay hav epoor
traction performance .
The saf espee don awet ,snow covered or icy
road is always lower than on dry road surfa-
ces.
You should pay special attention to road con-
dition swhen temperatures are aroun dfreez -
ing point.
Mercedes-Benz recommends aminimum
tread dept hof ã in (4 mm )on all four winte r
tires . Observ eth elegall yrequire dminimum
tire tread dept h (
Ypage 363). Winte rtires can
reduce th ebraking distanc eon snow-covered
surfaces in comparison wit h summer tires.
The braking distanc eis still muc hfurther than
376All about wheels and tires
Wheels and tires
Page 379 of 410

on surfaces that are not icy or covered with
snow. Take appropriate care when driving.
Further information on winter tires (M+S
tires) (
Ypage 364).
Temperature
GWARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, underinfla-
tion, or excessive loading, either separately or
in combination, can cause excessive heat
build-up and possible tire failure.
The temperature grades are A (the highest), B,
and C. They represent the tire's resistance to
the generation of heat and its ability to dissi-
pate heat when tested under controlled con-
ditions on a specified indoor laboratory test
wheel. Sustained high temperature can cause
the material of the tire to degenerate and
reduce tire life, and excessive temperature
can lead to sudden tire failure. The grade C
corresponds to a level of performance which
all passenger car tires must meet under the
Federal Motor Vehicle Safety Standard No.
109. Grades B and A represent higher levels
of performance on the laboratory test wheel
than the minimum required by law.
Tire labeling
Overview
:Uniform Tire Quality Grading Standard
(
Ypage 381)
;DOT, Tire Identification Number
(
Ypage 380)
=Maximum tire load (Ypage 380)
?Maximum tire pressure (Ypage 368)
AManufacturer
BTire material (Ypage 381)
CTire size designation, load-bearing capa-
city and speed rating (
Ypage 377)
DLoad index (Ypage 379)
ETire name
The markings described above are on the tire
in addition to the tire name (sales designa-
tion) and the manufacturer's name.
iTire data is vehicle-specific and may devi-
ate from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
GWARNING
Exceeding the stated tire load-bearing capa-
city and the approved maximum speed could
lead to tire damage or the tire bursting. There is a risk of accident.
All about wheels and tires377
Wheels and tires
Z
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Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.
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 descrip- tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing 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. manu-
facturing standards.
If "T" precedes the size description: compact
emergency wheels with high tire pressure
that are only designed for temporary use in an
emergency.
Tire width: tire width:shows the nominal
tire width in millimeters.
Height-width ratio: aspect ratio;is the
size ratio between the tire height and 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 man-
ufacturer (e.g. 245/40 ZR 18).
Rim diameter:
rim diameter?is the diam-
eter of the bead seat, not the diameter of the
rim flange. The rim diameter is specified in
inches (in).
Load-bearing index: load-bearing indexA
is a numerical code that specifies the maxi-
mum load-bearing capacity of a tire.
Do not overload the tires by exceeding the
specified load limit. The maximum permissi-
ble load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side (Ypage 372).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can
bear. For further information on the maximum tire load in kilograms and lbs, see
(
Ypage 380).
For further information on the load bearing
index, see "Load index" (
Ypage 379).
Speed rating: speed ratingBspecifies the
approved maximum speed of the tire.
iTire data is vehicle-specific and may devi-
ate from the data in t
he example.
Regardless of the speed rating, always
observe the speed limits. Drive carefully and
adapt your driving style to the traffic condi-
tions.
Summer tires
IndexSpeed rating
Qup to 100 mph (160 km/h)
Rup to 106 mph (170 km/h)
Sup to 112 mph (180 km/h)
Tup to 118 mph (190 km/h)
Hup to 130 mph (210 km/h)
Vup to 149 mph (240 km/h)
378All about wheels and tires
Wheels and tires
Page 381 of 410

IndexSpeed rating
Wup to 168 mph (270 km/h)
Yup to 186 mph (300 km/h)
ZR...Yup to 186 mph (300 km/h)
ZR...(..Y)over 186 mph(300km/ h)
ZRover 149 mph (240km/ h)
ROptionally, 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 ZR18).
The service specification is made up of
load-bearing index Aand speed rating B.
RIf the size description of your tire includes
"ZR" and there are no service specifica-
tions, ask the tire manufacturer in order to
find out the maximum speed.
If a service specification is available, the
maximum speed is limited according to the
speed rating in the service specification.
Example: 245/40 ZR18 97 Y.In this exam-
ple, "97 Y" is the service specification. The
letter "Y" represents the speed rating. The
maximum speed of the tire is limited to
186 mph (300 km/h).
RThe size description for all tires with maxi-
mum speeds of over 186 mph (300 km/h)
must include "ZR", andthe service specifi-
cation must be given in parentheses. Exam-
ple: 275/40 ZR 18 (99 Y). Speed rating
"(Y)" indicates that the maximum speed of
the tire is over 186 mph (300 km/h). Ask
the tire manufacturer about the maximum
speed.
All-weather tires and winter tires
IndexSpeed rating
Q M+S1up to 100 mph (160 km/h)
T M+S1up to 118 mph (190 km/h)
IndexSpeed rating
H M+S1up to 130 mph (210 km/h)
V M+S1up to 149 mph (240 km/h)
iNot all tires with the M+S marking provide
the driving characteristics of winter tires. In
addition to the M+S marking, winter tires
also have the isnowflake symbol on
the tire wall. Tires with this marking fulfill
the requirements of the Rubber Manufac-
turers Association (RMA) and the Rubber
Association of Canada (RAC) regarding the
tire traction on snow. They have been espe-
cially developed for driving on snow.
An electronic speed limiter prevents your
vehicle from exceeding a speed of 130 mph
(210 km/h).
The speed rating of tires mounted at the fac-
tory may be higher than the maximum speed
that the electronic speed limiter permits.
Make sure that your tires have the required
speed rating, e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "Tires" section (
Ypage 388).
Further information about reading tire data
can be obtained from any qualified specialist workshop.
Load index
In addition to the load-bearing index, load
index :may also be imprinted on the side-
wall of the tire. You will find this after the let-
1Or M+S ifor winter tires.
All about wheels and tires379
Wheels and tires
Z
Page 382 of 410

ter that identifies the speed rating
(
Ypage 377).
RIf no specification is given: no text (as in the
example above), represents a standard
load (SL) tire
RXL or Extra Load: represents a reinforced
tire
RLight Load: represents a light load tire
RC, D, E: represents a load range that
depends on the maximum load that the tire
can carry at a certain pressure
iTire data is vehicle-specific and may devi-
ate from the data in the example.
Maximum load rating
Maximum tire load :is the maximum per-
missible weight for which the tire is approved.
Do not overload the tires by exceeding the
specified load limit. The maximum permissi-
ble load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on the driver's side (
Ypage 372).
iThe actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
DOT, Tire Identification Number (TIN)
US tire regulations stipulate that every tire
manufacturer or retreader must imprint a TIN in or on the sidewall of each tire produced.
The TIN is a unique identification number. The
TIN enables the tire manufacturers or retread-
ers to inform purchasers of recalls and other
safety-relevant matters. It makes it possible
for the purchaser to easily identify the affec-
ted tires.
The TIN is made up of manufacturer identifi-
cation code ;, tire size=, tire type code ?
and manufacturing date A.
DOT (Department of Transportation): tire
symbol :marks that the tire complies with
the requirements of the U.S. Department of
Transportation.
Manufacturer identification code: manu-
facturer identification code ;provides
details on the tire manufacturer. New tires
have a code with two symbols. Retreaded
tires have a code with four symbols.
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 ma nufa
cture.
For example, a tire that is marked with
"3208", was manufactured in week 32 in
2008.
iTire data is vehicle-specific and may devi-
ate from the data in the example.
380All about wheels an d tires
Wheels and tires
Page 383 of 410

Tire characteristics
This information describes the type of tire
cord and the number of layers in sidewall:
and under tire tread ;.
iTire data is vehicle-specific and may devi-
ate 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 U S Department of Transportation.
Normal occupant weight
The number of occupants for which the vehi-
cle is designed multiplied by 68 kilograms
(150 lb s).
Unifor m Tire Quality Grading Standards
A uniform standard to grade the quality of
tires with regards to tread quality, tire traction
and temperature characteristics. The quality
grading assessment is made by the manufac-
turer following specifications from the U.S. government. The ratings are molded into the
sidewall of the tire.
Recommended tire pressures
The recommended tire pressure applies to
the tires mounted at the factory.
The Tire and Loading Information placard con-
tains the recommended tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissibl
e ve
hicle speed.
The tire pressure table contains the recom-
mended pressures for cold tires for various
operating conditions, i.e. differing load and
speed conditions.
Increased vehicle weight due to optional
equipment
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.
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 identifica-
tion. 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, lug-
gage and the drawbar noseweight, if applica-
ble. The gross vehicle weight must not exceed
the gross vehi
cle weight rating GVWR as
specified on the vehicle identification plate on the B-pillar on the driver's side.
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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, occu-
pants, fuel, luggage and the drawbar nose-
weight, if applicable). The gross vehicle
weight rating is specified on the vehicle iden-
tification plate on the B-pillar on the driver's
side.
Maximum loaded vehicle weight
The maximum weight is the sum of:
Rthe curb weight of the vehicle
Rthe weight of the accessories
Rthe load limit
Rthe weight of the factory installed optional
equipment
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure is bar. 100 kilopascals (kPa) are the equiva-
lent 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 capa-
city more precisely.
Curb weight
The weight of a vehicle with standard equip-
ment including the maximum capacity of fuel,
oil and coolant. It also includes the air-condi-
tioning 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 is the maximum
permissible weight in kilograms or lbs 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.
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
su
rface. 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.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
Rif 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
parts and more than 5 lbs (2.3 kg). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-
382All about wheels and tires
Wheels and tires