2011 MERCEDES-BENZ G55AMG Owner's Manual

DLoad index (Y page 265)ETire name
i
Tire data is vehicle-specific and may
deviate from the data in the example.
Indication of tire size, load-bearing
capacity and speed index
:Tire width;Nominal aspect ration in %=Tire code?Rim diameterALoad bearing indexBSpeed index
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
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 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 that 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.
Tire labeling263Wheels and tiresZ

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 260).
For further information on the load bearing
index, see Load index ( Y page 265).
Speed index: speed index B specifies the
approved maximum speed of the tire.GWarning
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 index, always
observe the speed limits. Drive carefully and
adapt your driving style to the traffic
conditions.
Summer tiresIndexSpeed ratingQUp 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)WUp to 168 mph (270 km/h)YUp to 186 mph (300 km/h)ZR...YUp to 186 mph (300 km/h)Summer tiresIndexSpeed ratingZR...(..Y)above 186 mph (300 km/h)ZRabove 149 mph (240 km/h)
R Optionally, tires with a maximum speed
rating of more than 149 mph (240 km/h)
may have "ZR" in the size description
depending on the manufacturer (e.g.
245/40 ZR 18).
The service specification is made up of load
bearing index A and speed index B.
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 index 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 index
and the maximum speed of the tire is
limited to 186 mph (300 km/h).
R Every tire that has a maximum speed rating
of more than 186 mph (300 km/h) must
have "ZR" in the size description and the
service specification must be given in
brackets. Example: 275/40 ZR 18 (99 Y).
The speed index "(Y)" shows that the
maximum speed of the tire is above
186 mph (300 km/h). Ask the tire
manufacturer to find out the maximum
speed.
All-weather tires and winter tiresIndexSpeed ratingQ M+S 21up to 100 mph (160 km/h)T M+S21up to 118 mph (190 km/h)21
or M+S i for winter tires.264Tire labelingWheels and tires

All-weather tires and winter tiresIndexSpeed ratingH M+S21up to 130 mph (210 km/h)V M+S21up 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 i snowflake symbol on the tire wall.
Tires with this marking 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.
An electronic speed limiter prevents your
vehicle from exceeding a speed of
130 mph (210 km/h).
The speed index 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 index as specified in the "tires" section
( Y page 272), e.g. if you buy new tires.
Further information about reading tire data
can be obtained from any qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center.
Load identification
i Tire data is vehicle-specific and may
deviate from the data in the example.
In addition to the load bearing index, load
index : may be imprinted after the letters
that identify speed index B(Y page 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
DOT, Tire Identification Number (TIN)
U.S. tire regulations prescribe that every
manufacturer of new tires or retreader has to
imprint a TIN in or on the sidewall of each tire
produced.
21 or M+S i for winter tires.Tire labeling265Wheels and tiresZ

The TIN is a unique identification number. The
TIN enables the tire manufacturers to inform
purchasers of recalls and other safety-
relevant matters. It makes it possible for the
purchaser to easily identify the affected tires.
The TIN is made up of manufacturer
identification code ;, tire size =, tire type
code ? and manufacturing date A.
i Tire data is vehicle-specific and may
deviate from the data in the example.
DOT (Department of Transportation): tire
symbol : marks that the tire complies with
the requirements of the U.S. Department of
Transportation.
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 246).
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.
Characteristics of the tire
i Tire data is vehicle-specific and may
deviate from the data in the example.
This information describes the type of tire
cord and the number of layers in
sidewall : and under tire tread ;.
Definitions for tires and loading
Tire structure and characteristics
Describes the number of layers or the number
of rubber-coated belts in the tread and the
sidewall of the tire. 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 United States Department of
Transportation.
266Definitions for tires and loadingWheels and tires

Average weight of the vehicle
occupants
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. The quality
grading assessment is made by the
manufacturer following specifications from
the U.S. government. The quality grade of a
tire is imprinted on the sidewall of the tire.
Recommended tire pressure
The recommended tire pressure for your
vehicle under normal driving conditions. You
will find the recommendation on the Tire and
Loading Information placard on the B-pillar on
the driver's side of your vehicle. The
recommended tire pressure provides the best
balance between handling characteristics,
ride comfort and wear. Additional information
on particular driving conditions is located on
the tire pressure table on the inside of the fuel
filler flap.
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.
Wheel 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 index
The speed index is part of the tire
identification. It specifies the speed range for
which the tire is approved.
GTW (Gross Trailer Weight)
The GTW is the sum of the weight of a trailer
and the weight of the load, luggage,
accessories etc. on the trailer.
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 permitted gross
weight of the fully laden vehicle (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 weight of the laden vehicle
The maximum weight is the sum of the curb
weight of the vehicle, the weight of the
Definitions for tires and loading267Wheels and tiresZ

accessories, the maximum load and the
weight of the optional equipment installed at
the factory.
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa is the
equivalent of 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 and also includes the
air-conditioning system and optional
equipment if these are installed on the
vehicle, but does not include passengers or
luggage.
Maximum tire load
The maximum tire load 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)
Standard unit of measurement 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 every 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 3 hours or not have traveled more than
1.6 km (1 mile) in this time.
Tire tread
The part of the tire that comes into contact
with the road.
Tire 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
tire 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
268Definitions for tires and loadingWheels and tires

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 identification number 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.
TWR (permissible trailer drawbar
noseweight)
The TWR is the maximum permissible weight
that may act on the ball coupling of the trailer
tow hitch.
Wear indicator
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.
Distribution of the vehicle occupants
Distribution of vehicle occupants over
designated seat positions in a vehicle.
Maximum permissible payload
weight
Nominal load and luggage load plus
68 kilograms (150 lb) multiplied by the
number of seats in the vehicle.
Changing a wheel
Flat tire
The "Roadside Assistance" section
( Y page 232) 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.
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 no
warranty book is available, the tires should be
rotated every 3000 to 6000 miles
(5000 to 10000 km), or earlier if tire wear
Changing a wheel269Wheels and tiresZ

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
reactivate the tire pressure monitor
( Y page 253) if necessary.
Information on changing a wheel and
mounting the spare wheel ( Y page 232).
! On vehicles installed with a tire pressure
monitor, electronic components are
located in the wheel.
Tire-mounting tools should not be applied
in the area of the valve, as 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 install the spare wheel against the
direction of rotation. Adhere to the time
restriction on use as well as the speed
limitation specified on the spare wheel.
Storing wheels
Store tires 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
GWarning
Do not use power washers with circular jet
nozzles (concentrated-power jets) to clean
your vehicle, especially for cleaning tires. You
could otherwise damage the tires and cause
an accident.
Wheel and tire combinations
Please bear the following in mind
GWarning
Replace rims or tires with the same
designation, manufacturer and type as shown
on the original part. For further information
contact an authorized Mercedes-Benz Center.
If incorrectly sized rims and tires are
mounted, the wheel brakes or suspension
components can be damaged. Also, the
operating clearance of the wheels and the
tires may no longer be correct.
GWarning
Worn, old tires can cause accidents. If the tire
tread is worn to minimum tread depth, or if
the tires have sustained damage, replace
them.
When replacing rims, only use genuine
Mercedes-Benz wheel bolts specified for the
particular rim type. Failure to do so can result
in the bolts loosening and possibly an
accident.
Retreaded tires are not tested or
recommended by Mercedes-Benz, since
previous damage cannot always be
recognized on retreads. The operating safety
of the vehicle cannot be assured when such
tires are used.
GWarning
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possible
damage to your vehicle has occurred, you
should turn on the hazard warning flashers,
carefully slow down, and drive with caution to
an area which is a safe distance from the road.
Inspect the tires and the vehicle underbody
for possible damage. If the vehicle appears
unsafe, have the vehicle towed to the nearest
270Wheel and tire combinationsWheels and tires