2016 MERCEDES-BENZ CLA-Class Owner's Manual

Step 3
Example 1Example 2Example 3
Permissible load
(maximum gross vehi-
cle weight rating from
the Tire and Loading
Information placard
minus the gross
weight of all occu-
pants)1500 lbs (680 kg)Ò
750 lbs (340 kg) =
750 lbs (340 kg)1500 lbs (680 kg) Ò
540 lbs (245 kg)
=960 lbs (435 kg)1500 lbs (680 kg) Ò
150 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 339).
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.
All about wheels and tires
Uniform Tire Quality Grading Stand-
ards
Overview of Tire Quality Grading Stand-
ards
Uniform Tire Quality Grading Standards are
U.S. government specifications. Their pur-
pose is to provide drivers with uniform relia-
ble information on tire performance data. Tire
manufacturers have to grade tires using three
performance factors: :tread wear grade, ;
traction grade and =temperature grade.
These regulations do not apply to Canada.
Nevertheless, all tires sold in North America
are provided with the corresponding quality
grading markings on the sidewall of the tire.
Quality grades can be found, where applica-
ble, on the tire sidewall between tread shoul-
der and maximum section width.
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Example:
RTreadwear grade:200
RTraction grade:AA
RTemperature grade: A
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
iThe actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. government 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, how-
ever, and may depart significantly from the
norm due to variations in driving habits, ser-
vice practices and differences in road char-
acteristics and climate.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
!Avoid wheelspin. This can lead to damage
to the drive train.
The traction grades – from highest to lowest –
are AA, A, B and C. Those grades represent
the tire's ability to stop on wet pavement as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance. The safe speed on a wet, snow covered or icy
road is always lower than on dry road surfa-
ces.
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
Mercedes-Benz recommends a minimum
tread depth of
ãin (4 mm) on all four winter
tires. Observe the legally required minimum
tire tread depth (
Ypage 329). Winter tires can
reduce the braking distance on snow-covered
surfaces in comparison with summer tires.
The braking distance is still much further than
on surfaces that are not icy or covered with
snow. Take appropri ate ca
re when driving.
Further information on winter tires (M+S
tires) (
Ypage 330).
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, representing 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.
344All about wheels an d tires
Wheels and tires

Tire labeling
Overview
:Uniform Tire Quality Grading Standards
(
Ypage 349)
;Department of Transportation, Tire Iden-
tification Number (
Ypage 348)
=Maximum load rating (Ypage 347)
?Maximum tire pressures (Ypage 334)
AManufacturer
BTire material (Ypage 348)
CTire size designation, load-bearing capa-
city and speed rating (
Ypage 345)
DLoad index (Ypage 347)
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.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.
:Tire width
;Nominal aspect ratio in %
=Tire code
?Rim diameter
ALoad bearing index
BSpeed rating
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: compactemergency 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.
Aspect ratio: aspect ratio;is the size ratio
between the tire height and tire width and is
shown in percent. The aspect ratio is calcu-
All about wheels an d tires345
Wheels and tires
Z

lated 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 339).
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 347).
For further information on the load bearing
index, see "Load index" (
Ypage 347).
Speed rating: speed ratingBspecifies the
approved maximum speed of the tire.
iTire data is vehicle-specific and may devi-
ate from the data in the 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)
IndexSpeed rating
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)
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.
346All about wheels and tires
Wheels and tires

All-weather tires and winter tires
IndexSpeedrating
Q M+S1up to 100 mph (160 km/h)
T M+S1up to 118 mph (190 km/h)
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 driv ing characteristics of winter tires. In
addit ion 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-
cial lydeveloped for driving on snow.
An electronic speed limiter prevents your
veh icle from exceeding a speed of 130 mph
(21 0km/ 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 355).
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 be imprinted after the letters
that identify speed rating on the sidewall of
the tire. Speed rating (
Ypage 345).
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-
1Or M+S ifor winter tires.
All about wheels and tires347
Wheels and tires
Z

ble load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side (
Ypage 339).
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.
For further information about retreaded tires,
see (
Ypage 355).
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.
iTire data is vehicle-specific and may devi-
ate from the data in the example.
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.
348All about wheels and tires
Wheels and tires

DOT (Department of Transportation)
DOT-markedtires fulfill th erequirements of
th e U S Departmen tof Transportation .
Normal occupant weigh t
The number of occupant sfo rwhic hth evehi-
cle is designed multiplie dby 68 kilograms
(15 0lbs) .
Unifor mTire Qualit yGrading Standards
A uniform standard to grade th equalit yof
tires wit hregards to tread quality, tire traction
and temperature characteristics .The qualit y
gradin gassessmen tis made by th emanufac -
turer following specification sfrom th eU.S.
government. The ratings are molded into th e
sidewall of th etire.
Recommended tire pressure s
The recommended tire pressur eapplies to
th etires mounted at th efactory.
The Tir eand Loadin gInformation placard con-
tains th erecommended tire pressures fo r
cold tires on afull yloade dvehicl eand fo rth e
maximum permissibl evehicl espeed.
The tire pressur etable contain sth erecom-
mended pressures fo rcold tires fo rvarious
operating conditions, i.e. differin gload and
speed conditions.
Increased vehicle weigh tdu eto optiona l
equipment
The combine dweight of all standard and
optional equipmen tavailable fo rth evehicle,
regardless of whether it is a
ctually installed
on th evehicl eor not.
Ri m
This is th epart of th ewhee lon whic hth etire
is mounted.
GAW R(Gross Axle Weight Rating)
The GAW Ris th emaximum gross axl eweight
rating. The actual load on an axl emus tnever
exceed th egross axl eweight rating. The
gross axl eweight ratin gcan be found on th e
vehicl eidentification plat eon th eB-pillar on
th edriver's side . Speed rating
The speed ratin
gis part of th etire identifica-
tion .It specifies th espeed range fo rwhic hth e
tire is approved.
GV W(Gross Vehicle Weight )
The gross vehicl eweight includes th eweight
of th evehicl eincludin gfuel ,tools ,th espar e
wheel, accessories installed ,occupants, lug-
gage and th edrawbar noseweight ,if applica-
ble. The gross vehicl eweight mus tno texceed
th egross vehicl eweight ratin gGVWR as
specified on th evehicl eidentification plat eon
th eB-pillar on th edriver's side .
GVWR (Gross Vehicle Weight Rating)
The GVWR is th emaximum permissibl egross
weight of afull yloade dvehicl e(the weight of
th evehicl eincludin gall accessories, occu-
pants ,fuel, luggage and th edrawbar nose-
weight ,if applicable). The gross vehicl e
weight ratin gis specified on th
eve
hicl eiden -
tification plat eon th eB-pillar on th edriver's
side .
Maximum loaded vehicle weigh t
The maximum weight is th esum of :
Rthecur bweight of th evehicl e
Rtheweight of th eaccessories
Rth eload limi t
Rtheweight of th efactory installed optional
equipmen t
Kilopascal (kPa)
Metric uni tfo rtire pressure. 6. 9kP acorre-
spond sto 1psi .Another uni tfo rtire pressur e
is bar. 10 0kilopascal s(kPa) are th eequiva-
len tof 1bar.
Load index
In addition to th eload-bearin gindex ,th eload
index may also be imprinte don th esidewall of
th etire. This specifies th eload-bearin gcapa-
cit ymor eprecisely.
All about wheels and tires34 9
Wheels and tires
Z

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 tire load is the maximum per-
missible 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
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.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked with the tires
out of direct sunlight 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 sit
s
securely on t

he 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 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 accesso-
ries.
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 dis-
tributed over the tire tread. If the tire tread is
level with the bars, the wear limit of áin
(1.6 mm) has been reached.
350All about wheels and tires
Wheels and tires