
Keep batteries out of the reach of children.
Seek medical attention immediately if a
battery is swallowed. G
WARNING
The SmartKey batteries contain perchlorate
material, which may require special handling
and regard for the environment. Observe
government disposal guidelines. California
residents, see www.dtsc.ca.gov/
HazardousWaste/Perchlorate/
index.cfm.
Checking the battery X
Press the 0037or0036 button.
The SmartKey battery is working properly if
battery check lamp 0043lights up briefly.
If battery check lamp 0043does not light up
briefly during the test, the SmartKey battery
is discharged.
X Changing the battery (Y page 64)
i The battery can be obtained from any
authorized Mercedes-Benz Center.
i If the SmartKey battery is checked within
the signal range of the vehicle, pressing the
0037 or0036 button locks or unlocks the
vehicle.
Replacing the battery X
Take the mechanical key out of the
SmartKey (Y page 63).
You require a CR 2025 3 V cell battery. X
Press mechanical key 0044into the opening
in the SmartKey in the direction of the
arrow until battery tray cover 0043opens. Do
not hold the cover closed while doing so. X
Remove the cover of the battery tray.
X Repeatedly tap the SmartKey against your
palm until battery 0087falls out.
X Insert the new battery with the positive
terminal facing upwards. Use a lint-free
cloth to do so.
X Insert the front tabs of the battery tray's
cover first, and then press to close it.
X Check the function of all SmartKey buttons
on the vehicle. 64
SmartKeyOpening and closing

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 of tire labeling
The following markings are on the tire in
addition to the tire name (sales designation)
and the manufacturer's name: 0043
Uniform Tire Quality Grading Standard
(Ypage 267)
0044 DOT, Tire Identification Number
(Ypage 266)
0087 Maximum tire load (Y page 261)
0085 Maximum tire pressure (Y page 254)
0083 Manufacturer
0084 Tire material (Y page 266)
006B Tire size designation, load-bearing
capacity and speed rating (Y page 263)006C
Load index (Y page 265)
006D Tire 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
0043
Tire width
0044 Nominal aspect ratio in %
0087 Tire code
0085 Rim diameter
0083 Load bearing index
0084 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 Tire labeling
263Wheels and tires Z

pressure, to be used only temporarily in an
emergency.
Tire width: tire width0043shows the nominal
tire width in millimeters.
Nominal aspect ratio: aspect ratio0044is the
ratio between the tire height and tire width
and is shown as a percentage. The aspect
ratio is calculated by dividing the tire width by
the tire height.
Tire code: tire code0087specifies 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 diameter0085is 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 index0083
is a numerical code which specifies the
maximum load-bearing capacity of a tire. G
WARNING
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. G
WARNING
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 261).
For further information on the load bearing
index, see Load index (Y page 265).
Speed rating: speed rating0084specifies the
approved maximum speed of the tire. G
WARNING
Even when permitted by law, never operate a
vehicle at speeds greater than the maximum
speed rating of the tires.
Exceeding the maximum speed for which tires
are rated can lead to sudden tire failure,
causing loss of vehicle control and possibly
resulting in an accident and/or serious
personal injury and possible death, for you
and for others.
Regardless of the speed rating, always
observe the speed limits. Drive carefully and
adapt your driving style to the traffic
conditions. Summer tires
Index Speed rating
Q Up to 100 mph (160 km/h)
R Up to 106 mph (170 km/h)
S Up to 112 mph (180 km/h)
T Up to 118 mph (190 km/h)
H Up to 130 mph (210 km/h)
V Up to 149 mph (240 km/h)
W Up to 168 mph (270 km/h)
Y Up to 186 mph (300 km/h)
ZR...Y Up to 186 mph (300 km/h)
ZR...(..Y) Above 186 mph (300 km/h)
ZR Above 149 mph (240 km/h)264
Tire labelingWheels and tires

R
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).
The service specifications consist of load
bearing index 0083and speed rating 0084.
R If the size description of your tire includes
"ZR" and there are no service
specifications, 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 ZR 18 97 Y.In this
example, "97 Y" is the service specification.
The letter "Y" represents the speed rating,
and the maximum speed of the tire is
limited to 186 mph (300 km/h).
R Every tire that has a maximum speed above
186 mph (300 km/h) must have "ZR" in the
size description andthe service
specification must be given in brackets.
Example: 275/40 ZR 18 (99 Y). The speed
rating "(Y)" shows that the maximum speed
of the tire is above 186 mph (300 km/h).
Ask the tire manufacturer about the
maximum speed. All-weather tires and winter tires
Index Speed rating
Q M+S
13 Up to 100 mph (160 km/h)
T M+S
13 Up to 118 mph (190 km/h)
H M+S
13 Up to 130 mph (210 km/h)
V M+S
13 Up to 149 mph (240 km/h)
i
Not all tires that have the M+S
identification offer the driving
characteristics of winter tires. In addition
to the M+S marking, winter tires also have
the 004D snowflake symbol on the tire wall.
Tires with this identification fulfill the
requirements of the Rubber Manufacturers Association (RMA) and the Rubber
Association of Canada (RAC) regarding the
tire traction on snow and have been
especially developed for driving on snow.
The speed rating of tires mounted at the
factory may be higher than the maximum
speed that the electronic speed limiter
permits.
Make sure that your tires have the required
speed rating as specified in the "Tires"
section (Y page 270), e.g. if you buy new
tires.
Further information about reading tire data
can be obtained from any qualified specialist
workshop. Load index
i
Tire data is vehicle-specific and may
deviate from the data in the example.
In addition to the load-bearing index, load
index 0043may be imprinted after the letters
that identify speed rating 0084(Ypage 263) 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
13 Or M+S004D for winter tires. Tire labeling
265Wheels and tires Z

Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa is the
equivalent of 1 psi. Another unit for tire
pressure is bar. There are 100 kilopascals
(kPa) to 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. 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. For this,
the vehicle must have been stationary for at
least three hours or not have traveled more
than 1.6 km (1 mile) in this time. 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. 268
Definition of ter
ms for tires and loadingWheels and tires

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-voltage 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 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 229) 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. 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.
! 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.
Only have tires changed at a qualified
specialist workshop.
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 Changing a wheel
269Wheels and tires Z