2013 MERCEDES-BENZ SL-CLASS ROADSTER tires

Maximum permissible gross vehicle
weight rating
X
The Tire and Loading Information placard
gives you details on maximum permissible
gross vehicle weight rating : : "The gross
weight of occupants and luggage must
never exceed XXX kilograms or XXX
pounds."
The gross weight of all vehicle occupants,
load and luggage must not exceed the
specified value.
i The specifications shown on the Tire and
Loading Information placard in the
illustration are examples. The maximum
permissible gross vehicle weight rating is
vehicle-specific and

may differ from that in
the illustration. You can find the valid
maximum permissible gross vehicle weight
rating for your vehicle on the Tire and
Loading Information placard. Number of seats Maximum
number of seats
: determines
the
maximum number of occupants allowed to
travel in the vehicle. This information can be
found on the Tire and Loading Information
placard.
i The specifications shown on the Tire and
Loading Information placard in the
illustration are examples. The number of
seats is vehicle-specific and can differ from
the details shown. The number of seats in
your vehicle can be found on the Tire and
Loading Information placard. Determining the correct load limit
Step-by-step instructions The following steps have been developed as
required of all manufacturers under Title 49,
Code of U.S. Federal Regulations, Part 575
pursuant to the "National Traffic and Motor
Vehicle Safety Act of 1966".
X
Step 1: Locate the statement "The
combined weight of occupants and cargo
should never

exceed XXX kg or XXX lbs." on
your vehicle’s Tire and Loading Information
placard.
X Step 2: Determine the combined weight of
the
driver and passengers that will be riding
in your vehicle.
X Step 3: Subtract the combined weight of
the driver and passengers from XXX
kilograms or XXX lbs.
X Step 4: The resulting figure equals the
available amount

of cargo and luggage load
capacity. For example, if the "XXX" amount
equals 1400 lbs and there will be five
150 pound passengers in your vehicle, the
amount of available cargo and luggage load
capacity is 650 lbs (1400 – 750 (5 x 150)
= 650 lbs).
X Step 5: Determine the combined weight of
luggage and cargo being loaded on the
vehicle.

That weight may not safely exceed
the available cargo and luggage load
capacity calculated in step 4. 538
Loading the vehicle
Wheels and tires

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 maximum load of 1500 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 537).
The higher the weight of all the occupants, the
smaller the maximum load for luggage.
Step 1 Example
1 Example 2
Combined
maximum
weight of
occupants
and cargo
(data
from

the
Tire and
Loading
Information
placard) 1500 lbs
(680 kg) 1500 lbs
(680 kg)
Step 2
Example
1 Example 2
Number of
people in the
vehicle
(driver
and
occupants) 1 2
Weight of the
occupants
Occupant
1: 175 lbs
(80 kg) Occupant
1: 175 lbs
(80 kg)
Occupant
2: 195 lbs
(88 kg)
Gross weight
of all
occupants
175 lbs
(80 kg) 370 lbs
(168 kg) Step 3
Example 1 Example 2
Permissible
load
(maximum
gross vehicle
weight rating
from the Tire
and Loading
Information
placard minus
the gross
weight of all
occupants)
1500 lbs
(680 kg)
Ò
175 lbs
(80 kg) =
1325 lbs
(600 kg) 1500 lbs
(680 kg)
Ò
370 lbs
(168 kg) =
1130 lbs
(512 kg) 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 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
(Y page 537).
Permissible gross vehicle weight: the
gross weight of the vehicle, all passengers
and the load must not exceed the permissible
gross vehicle weight.
Gross axle weight rating: the maximum
permissible weight that can be carried by one
axle (front or rear axle).
To ensure that your vehicle does not exceed
the maximum permissible values (gross
vehicle weight and maximum gross axle
weight rating), have your loaded vehicle
(including driver, occupants and the load)
weighed on a suitable vehicle weighbridge. Loading the vehicle
539
Wheels and tires Z

All about wheels and tires
Uniform Tire Quality Grading
Standards
Overview of Tire Quality Grading
Standards Uniform Tire Quality Grading Standards are
U.S. government specifications. Their
purpose is to provide drivers with uniform
reliable
information
on tire performance data.
Tire manufacturers have to grade tires using
three performance factors: treadwear
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.
Where applicable, the tire grading
information can be found on the tire sidewall
between the tread shoulder and maximum
tire width.
Example:
R Treadwear grade: 200
R Traction grade: AA
R Temperature grade: A
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
i The 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,
however, and may depart significantly from
the norm, due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.
Traction G
WARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
! 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 a wet surface 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
surfaces.
You should pay special attention to road
conditions when temperatures are around
freezing point.
Mercedes-Benz recommends a minimum
tread depth of ã in (4 mm) on all four winter
tires. Observe the legally required minimum
tire tread depth (Y page 527). Winter tires can
reduce the braking distance on snow-covered
surfaces in comparison with summer tires.
The braking distance is still much further than 540
All about wheels and tires
Wheels and tires

on surfaces that are not icy or covered with
snow. Take appropriate care when driving.
Further information on winter tires (M+S
tires) (Y page 528).
Temperature
G
WARNING
The temperature grade for this tire is
established for a tire that is properly inflated
and not overloaded. Excessive speed,
underinflation, 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. These represent the tire's
resistance to the generation of heat and its
ability to dissipate heat when tested under
controlled conditions 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. Tire labeling
Overview :
Uniform Tire Quality Grading Standard
(Y page 545)
; DOT, Tire Identification Number
(Y page 544)
= Maximum tire load ( Y page 544)
? Maximum tire pressure (Y page 532)
A Manufacturer
B Tire material ( Y page 545)
C Tire size designation, load-bearing
capacity and speed index (
Y

page 541)
D Load index ( Y page 544)
E Tire name
The markings described above are on the tire
in addition to the tire name (sales
designation) and the manufacturer's 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 G
WARNING
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. All about wheels and tires
541
Wheels and tires
Z

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
A Load bearing index
B Speed 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
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 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.
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 537).
Example:
The load bearing index 91 indicates a
maximum load of 1356 lb (615 kg) that the
tires can bear. For further information on the
maximum tire load in kilograms and pounds,
see ( Y page 544).
For further information on the load bearing
index, see "Load index" ( Y page 544).
Speed rating: speed rating B specifies the
approved maximum speed of the tire.
i Tire data is vehicle-specific and may
deviate 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
conditions. 542
All about wheels and tires
Wheels and tires

Summe
r 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) over 186 mph (300 km/h)
ZR over 149 mph (240 km/h)
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 ZR18
).
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.
The maximum speed of the tire is limited to
186 mph (300 km/h).
R The size description for all tires with
maximum speeds of over 186 mph
(300 km/h) must include "ZR" and the
service specification must be given in parentheses. Example:
275/40
ZR

18 (99 Y). The 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. All-
weather
tires
and
winter
tires
Index Speed rating
Q M+S
2 up to 100 mph (160 km/h)
T M+S
2 up to 118 mph (190 km/h)
H M+S
2 up to 130 mph (210 km/h)
V M+S
2 up to 149 mph (240 km/h)
i
Not all

tires with the M+S marking provide
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. They
have been especially developed for driving
on snow.
An electronic speed limiter prevents your
vehicle from exceeding the following speeds:
R 130 mph (210 km/h):
-all vehicles (except AMG vehicles)
R 155 mph (250 km/h):
-SL 63 AMG
- SL 65 AMG
R 186 mph (300 km/h):
-SL 63 AMG (Performance Package)
- SL 65 AMG with increased maximum
speed
2 or M+S i for winter tires. All about wheels and tires
543
Wheels and tires Z

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,
e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "tires" section (Y page 552).
Further information about reading tire data
can be obtained from any qualified specialist
workshop.
Load index In addition to the load bearing index, load
rating : may be imprinted after the letters
that identify speed rating on the sidewall of
the tire (Y page 541).
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
i Tire data is vehicle-specific and may
deviate from the data in the example. Maximum load rating
Maximum load rating
: is the maximum
permissible weight for which the tire is
approved.
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 537).
i The actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
DOT, Tire Identification Number (TIN) U.S. tire regulations prescribe that every tire
manufacturer or

retreader must imprint a TIN
in or on the sidewall of every tire produced. The TIN is a unique identification number. The
TIN makes it easier for tire manufacturers or
retreaders to notify customers of recalls or
other safety-related matters. It makes it544
All about wheels and tiresWheels and tires

possible for the purchaser to easily identify
the affected tires.
The TIN consists of the manufacturer
identification code ;, tire size =, tire type
code ? and manufacturing date A.
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.
For further information about retreaded tires,
see ( Y page 526).
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.
i Tire data is vehicle-specific and may
deviate 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 ;.
i Tire data is vehicle-specific and may
deviate 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.
DOT (Department of Transportation)
DOT marked tires fulfill the requirements of
the United States Department of
Transportation.
Normal occupant weight
The number of occupants which the vehicle
is designed for, 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. Ratings are
determined by tire manufacturers using U.S.
government testing procedures. The ratings
are molded into the sidewall of the tire.
Recommended tire pressure
The recommended tire pressure applies to
the tires mounted at the factory.
The Tire and Loading Information placard
contains the recommended tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissible vehicle speed.
The tire pressure table contains the
recommended pressures for cold tires for All about wheels and tires
545
Wheels and tires Z