2012 MERCEDES-BENZ SLK-CLASS ROADSTER wheel size

Example: steps 1 to 3
The following table shows examples on how to calculate total and cargo load capacities with
varying seating configurations and number and size of occupants. The following examples use
a load limit of 1 500 lbs (680 kg). This is for illustration purposes only. Make sure you are
using the actual load limit for your vehicle stated on your vehicle's Tire and Loading Information
placard ( Y page 305).
Example 1Example 2Step 1Combined maximum
weight of occupants and
cargo (data from the Tire
and Loading Information
placard)1500 lbs (680 kg)1500 lbs (680 kg)Example 1Example 2Step 2Number of people in the
vehicle (driver and
occupants)12Weight of the occupantsOccupant 1: 175 lbs
(80 kg)Occupant 1: 175 lbs
(80 kg)
Occupant 2: 195 lbs)
(88 kgGross weight of all
occupants175 lbs (80 kg)370 lbs (168 kg)Example 1Example 2Step 3Permissible load and
trailer load/noseweight
(maximum permissible
load rating from the Tire
and Loading Information
placard minus the gross
weight of all occupants)1500 lbs (680 kg) -
175 lbs (80 kg) =
1325 lbs (600 kg)1500 lbs (680 kg) -
370 lbs (168 kg) =
1130 lbs (512 kg)
The higher the weight of all the occupants, the smaller the maximum load for luggage.
Further information can be found under "Towing a trailer" ( Y page 307).
Vehicle identification plate
Even if you have calculated the total load
carefully, you should still make sure that the
gross vehicle weight rating and the gross axleweight 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
( Y page 304).306Loading the vehicleWheels and tires

represent higher levels of performance on the
laboratory test wheel than the minimum
required by law.
Tire labeling
Tire labeling overview
The following markings are on the tire in
addition to the tire name (sales designation)
and the manufacturer's name:
:Uniform tire Quality Grading Standard
( Y page 313);DOT, Tire Identification Number
( Y page 311)=Maximum tire load ( Y page 307)?Maximum tire pressure ( Y page 300)AManufacturerBTire material ( Y page 312)CTire size designation, load-bearing
capacity and speed rating ( Y page 309)DLoad index ( Y page 311)ETire 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:Tire width;Nominal aspect ratio in %=Tire code?Rim diameterALoad bearing indexBSpeed 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
pressure, to be used only temporarily 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
Tire labeling309Wheels and tiresZ

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 149mph (240km/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.
Do not overload the tires by exceeding the
specified load limit. The maximum
permissible load can be found on the
vehicle's Tire and Loading Information
placard on the B-pillar on the driver's side
( Y page 304).
Example:
A load-bearing index of 91 indicates a
maximum load of 1,356lb (615 kg) that can be
carried by the tires. For further information on
the maximum tire load in kilograms and
pounds, see ( Y page 307).
For further information on the load-bearing
index, see Load index ( Y page 311).
Speed rating: speed rating B specifies the
approved maximum speed of the tire.GWARNING
Exceeding the stated tire load-bearing
capacity 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.
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 100mph (160 km/h)Rup to 106mph (170 km/h)Sup to 112mph (180 km/h)Tup to 118mph (190 km/h)Hup to 130mph (210 km/h)Vup to 149mph (240 km/h)Wup to 168mph (270 km/h)Yup to 186mph (300 km/h)ZR...Yup to 186mph (300 km/h)ZR...(..Y)over 186mph (300 km/h)ZRover 149mph (240 km/h)
R Optionally, tires with a maximum speed of
over 149 mph ( 240km/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 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 (300km/h).
R The size description for all tires with
maximum speeds of over 186mph
(300km/h) must include "ZR", and the
service specification must be given in
310Tire labelingWheels and tires

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 : 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. Retreaded
tires have a code with four symbols.
Further information about retreaded tires
( Y page 294).
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
the 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.
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.
312Definition of terms for tires and loadingWheels and tires

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
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 identification 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 á 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 lb), multiplied by the
vehicle's designated seating capacity.
Changing a wheel
Flat tire
The "Breakdown assistance" section
( Y page 275) 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
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.
Always pay attention to the instructions and
safety notes in the "Changing tires and
mounting the spare wheel" section
( Y page 276).
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 requires
this. 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 pressures.
For information on changing tires and
mounting the spare wheel, see (Y page 276).
Changing a wheel315Wheels and tiresZ

manufacturer in the vehicle document
wallet.
i Notes on the vehicle equipment – always
equip the vehicle with:
R tires of the same size on a given axle
(left/right)
R the same type of tires at a given time
(summer tires, winter tires, MOExtended
tires)
i On the following pages, you can find
information on approved wheel rims and
tire sizes for equipping your vehicle with
winter tires. Winter tires are not available
at the factory as standard equipment or
optional extras.
If you would like to equip your vehicle with
approved winter tires, you may also, in
certain circumstances, require rims of the
appropriate size. The sizes of the approved
winter tires may deviate from that of the
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.
i Overview of abbreviations used in the
following tire tables:
R BA: both axles
R FA: front axle
R RA: rear axle
In the following table, the wheel/tire
combinations are assigned to the vehicle
models through variants, e.g. V1, V2 etc.:V1SLK 250V2SLK 350V3SLK 55 AMG
i Not all wheel and tire combinations are
available at the factory for all countries.
Wheel and tire combinations317Wheels and tiresZ