2009 MERCEDES-BENZ SLR tires

286 OperationTires and wheelsTire ply material
1Plies in sidewall
2Plies under tread
This marking tells you about the type of
cord and number of plies in the sidewall
and under the tread.
Tire and loading terminology
Accessory weight
The combined weight (in excess of those
standard items which may be replaced) of
automatic transmission, power steering,
power brakes, power windows, power
seats, radio, and heater, to the extent that
these items are available as
factory-installed equipment (whether
installed or not).
Air pressure
The amount of air inside the tire pressing
outward on each square inch of the tire.
Air pressure is expressed in pounds per
square inch (psi), or kilopascal (kPa) or
bars.
Aspect ratio
Dimensional relationship between tire
section height and section width
expressed in percentage.Bar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi)
to 1 bar; there are 100 kilopascals (kPa)
to 1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least three hours or
driven no more than 1 mile (1.6 km).
Curb weight
The weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if so
equipped, air conditioning and additional
optional equipment, but without passen-
gers and cargo.
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

287 Operation
Tires and wheels
DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross A
xle W
eight R
ating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
certification label located on the driver’s
door A-pillar.
GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GVW must never exceed the
GVWR indicated on the certification label
located on the driver’s door A-pillar.GVWR (G
ross V
ehicle W
eight R
ating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
certification label located on the driver’s
door A-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to 1 psi; another metric unit for air
pressure is bars. There are
100 kilopascals (kPa) to 1 bar.
Maximum load rating
The maximum load in kilograms and
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
total load limit and production options
weight.Maximum tire inflation pressure
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lb).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.
Production options weight
The combined weight of those installed
regular production options weighing over
5 lb (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.

288 OperationTires and wheelsPSI (P
ounds per s
quare i
nch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
Recommended tire inflation pressure for
normal driving conditions is listed on the
Tire and Loading Information placard locat-
ed on the driver’s door B-pillar. Provides
best handling, tread life and riding com-
fort. If so equipped, supplemental informa-
tion pertaining to special driving situations
can be found on the tire inflation pressure
label on the inside of the fuel filler flap.
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated.
Sidewall
The portion of a tire between the tread and
the bead.TIN (T
ire I
dentification N
umber)
Unique identifier which facilitates efforts
by tire manufacturers to notify purchasers
in recall situations or other safety matters
concerning tires and gives purchases the
means to easily identify such tires. The TIN
is comprised of “Manufacturer’s identifica-
tion mark”, “Tire size”, “Tire type code”
and “Date of manufacture”.
Tire load rating
Numerical code associated with the
maximum load a tire can support.
Tire ply composition and material used
This indicates the number of plies or the
number of layers of rubber-coated fabric in
the tire tread and sidewall. Tire manufac-
turers also must indicate the ply materials
in the tire and sidewall, which include
steel, nylon, polyester, and others.Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is approved.
Total load limit
Rated cargo and luggage load plus
68 kilograms (150 lb) times the vehicle’s
designated seating capacity.
Traction
Force exerted by the vehicle on the road
via the tires. The amount of grip provided.
Tread
The portion of a tire that comes into
contact with the road.
Treadwear indicators
Narrow bands, sometimes called
“wear bars” that show across the tread of
a tire when only
1/16in (1.6 mm) of tread
remains.

289 Operation
Tires and wheels
Uniform Tire Quality Grading Standards
A tire information system that provides
consumers with ratings for a tire’s traction,
temperature and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The
ratings are molded into the sidewall of the
tire.
Vehicle maximum load on the tire
Load on an individual tire that is
determined by distributing to each axle its
share of the maximum loaded vehicle
weight and dividing it by two.
Rotating tires
Tire rotation can be performed on vehicles
with tires of the same dimension all
around. If your vehicle is equipped with
tires of the same dimension all around,
tires can be rotated, observing a
front-to-rear rotation pattern that will
maintain the intended rotation (spinning)
direction of the tire (
page 262).In some cases, such as when your vehicle
is equipped with mixed-size tires (different
tire dimension front vs. rear), tire rotation
is not possible.
If applicable to your vehicle’s tire configu-
ration, tires can be rotated according to
the tire manufacturer’s recommended in-
tervals in the tire manufacturer’s warranty
pamphlet located in your vehicle literature
portfolio. If none is available, tires should
be rotated every 3 000 to 6 000 miles
(5 000 to 10 000 km), or sooner if neces-
sary, according to the degree of tire wear.
The same rotation (spinning) direction
must be maintained (
page 262).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
!
A wheel change should only be carried out
at an authorized Mercedes-Benz Center. Other-
wise there is a danger of damaging the vehicle by
jacking it up incorrectly.
Warning!
G
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.

290 OperationTires and wheelsThoroughly clean the mounting face of
wheels and brake disks, i.e. the inner side
of the wheels/tires, during each rotation.
Check for and ensure proper tire inflation
pressure.
For information on wheel change, see the
“Practical hints” section (
page 365).
Anti-theft wheel nuts
Your vehicle is equipped with anti-theft
wheel nuts that prevent the theft of your
vehicle’s wheels.
1Anti-theft wheel nut
2Wheel nut key
Removing anti-theft wheel nuts

Unscrew anti-theft wheel nut1 using
wheel nut key2.

Replace anti-theft wheel nut1 with
one of the regular wheel bolts.

Fasten the wheel bolt and tighten it
with a torque wrench to a tightening
torque of 95 lb-ft (130 Nm).
Warning!
G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
95 lb-ft (130 Nm).
Only use Genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.
Warning!
G
Pull the parking brake lever up as many
notches as possible and move the gear se-
lector lever to park positionP, before loos-
ening the wheel bolts. Otherwise the vehicle
may move and cause an accident and/or
serious personal injury. !
Do not use air tools, such as an impact
wrench, when installing or removing the
anti-theft wheel nuts. An impact wrench can
damage the anti-theft wheel nuts and the wheel
nut key, or cause them to malfunction.
!
Store wheel bolts and anti-theft wheel nuts
not currently in use in a safe place to avoid
damage to the threads.

291 Operation
Tires and wheels
Fitting anti-theft wheel nuts
Unscrew a wheel bolt from one of the
wheels.

Replace that wheel bolt with one of the
anti-theft wheel nuts1 delivered with
your vehicle.

Fasten anti-theft wheel nut1 using
wheel nut key2 and tighten with a
torque wrench to a tightening torque of
95 lb-ft (130 Nm).Warning!
G
The wheels could come loose if the wheel
bolts are not tightened to a torque of 95 lb-ft
(130 Nm). Have the tightening torque
checked after changing a wheel.
Warning!
G
The wheels could come loose if the wheel
bolts are not tightened to a torque of 95 lb-ft
(130 Nm). Have the tightening torque
checked after changing a wheel.i
Keep the anti-theft wheel nut key in a conve-
nient place in your vehicle where you and service
personnel can always find it easily when it is
needed.
i
If you should lose the anti-theft wheel nut
key or one of the anti-theft wheel nuts, please
contact an authorized Mercedes-Benz Center for
a replacement.

292 OperationWinter drivingBefore the onset of winter, have your
vehicle winterized at an authorized
Mercedes-Benz Center. This service
includes:

Check of anticorrosion and antifreeze
concentration.


Addition of cleaning concentrate to the
water of the windshield and headlamp
cleaning system. Add MB Concentrate
“MB Summerfit” to a premixed wind-
shield washer solvent/antifreeze
which is formulated for below freezing
temperatures (
page 401).


Battery test. Battery capacity drops
with decreasing ambient temperature.
A well charged battery helps to make
sure that the engine can be started,
even at low ambient temperatures.


Tire change. Mercedes-Benz recom-
mends M+S rated radial-ply tires with a
minimum tread depth of approximately 1/6in (4 mm) on all four wheels for the
winter season.
Winter tires*
Always use winter tires at temperatures
below 45°F (7°C) and whenever wintry
road conditions prevail. Not all M+S rated
tires provide special winter performance.
Make sure the tires you use show the
mountain/snowflake.marking on the
tire sidewall. These tires meet specific
snow traction performance requirements
of the Rubber Manufacturers Association
(RMA) and the Rubber Association of Can-
ada (RAC) and have been designed specif-
ically for use in snow conditions. Use of
winter tires is the only way to achieve the
maximum effectiveness of the ABS and
ESP
® in winter operation.
For safe handling, make sure that all
mounted winter tires are of the same make
and have the same tread design.Always observe the speed rating of the
winter tires installed on your vehicle. If the
maximum speed for which your tires are
rated is below the speed rating of your
vehicle, you must place a notice to this
effect where it will be seen by the driver.
Such notices are available from your tire
dealer or from any authorized
Mercedes-Benz Center.
After you have fitted the winter tires,
restart the TPMS (
page 274).
!
A wheel change should only be carried out
at an authorized Mercedes-Benz Center. Other-
wise there is a danger of damaging the vehicle by
jacking it up incorrectly.
Warning!
G
Winter tires with a tread depth of less than 1/6in (4 mm) must be replaced. They are no
longer suitable for winter operation, in par-
ticular because they do not provide suffi-
cient grip. This could cause you to lose
control of your vehicle and cause an acci-
dent.

293 Operation
Winter driving
Snow chains
Snow chains should only be driven on
snow-covered roads at speeds not to
exceed 30 mph (50 km/h). Remove chains
as soon as possible when driving on roads
without snow.Please observe the following guidelines
when using snow chains:


Use of snow chains is not permissible
with all wheel/tire combinations.


Snow chains should only be used on
the rear wheels. Follow the manufac-
turer’s mounting instructions.


Only use snow chains that are
approved by Mercedes-Benz. Any au-
thorized Mercedes-Benz Center will be
glad to advise you on this subject.


Use of snow chains may be prohibited
depending on location. Always check
local and state laws before installing
snow chains.
i
When driving with snow chains, you may
wish to deactivate the ESP
® (page 86) before
setting the vehicle in motion. This will improve
the vehicle’s traction.
!
If snow chains are mounted to the front
wheels, they may scrape against the body or axle
components. The tires or the vehicle could be
damaged as a result.
!
Use of snow chains is not permissible with
tire sizes:


255/35 ZR19 (96Y) XL (Summer tires only)


295/30 ZR19 (100Y) XL


295/35 ZR18 (99Y)