2012 MERCEDES-BENZ SLS AMG ROADSTER wheel size

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 which 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.
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 263).
For further information on the load bearing
index, see Load index ( Y page 267).
Speed rating: speed rating 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 rating, 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)ZR...(..Y)Above 186 mph (300 km/h)ZRAbove 149 mph (240 km/h)266Tire labelingTires and wheels

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 ZR 18).
The service specifications consist of load
bearing index A and speed rating 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 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 and the 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 tiresIndexSpeed ratingQ M+S 18Up to 100 mph (160 km/h)T M+S18Up to 118 mph (190 km/h)H M+S 18Up to 130 mph (210 km/h)V M+S18Up 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 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 272), 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 : may be imprinted after the letters
that identify speed rating B(Y page 265) 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
18 Or M+S i for winter tires.Tire labeling267Tires and wheelsZ

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.
The TIN is a unique identification number. The
TIN enables 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 : indicates 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.
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.
Tire characteristics
i Tire data is vehicle-specific and may
deviate from the data in the example.
This information describes the tire cord and
the number of layers in sidewall : and under
tire tread ;.
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. There are
14.5038 pounds per square inch (psi) to
1 bar; there are 100 kilopascals (kPa) to 1 bar.
DOT (Department of Transportation)
DOT marked tires fulfill the requirements of
the United States Department of
Transportation.
268Definition of terms for tires and loadingTires and wheels

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 "Roadside Assistance" section
( Y page 233) 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.
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 this is not
available, the tires should then be replaced
every 3000 to 6000 miles
( 5000 to 10,000 km), or earlier if the tire wear
Changing a wheel271Tires and wheelsZ

pressures regularly, and only when the tires
are cold. Comply with the maintenance
recommendations of the tire manufacturer.
These are located in the vehicle document
wallet.
For further information on the recommended
tire inflation pressure and on tire pressures
for specific driving conditions ( Y page 253).
i Notes on the vehicle equipment – always
equip the vehicle:
R with tires of the same size on a given axle
(left/right)
R with the same type of tires on all wheels
at a given time (summer tires, winter
tires)
i The following pages contain information
on approved wheel rims and tire sizes for
equipping your vehicle with winter tires.
Winter tires are not available ex factory as
standard equipment or optional extras.
If you wish to equip your vehicle with
approved winter tires, you will also require,
in certain circumstances, wheel rims of an
appropriate size, as the sizes of approved
winter tires can deviate from those of
standard tires. This is dependent on the
model and the equipment installed at the
factory.
The tires and wheel rims, as well as further
information, can be obtained at a qualified
specialist workshop.Wheel and tire combinations273Tires and wheelsZ