2009 MERCEDES-BENZ SLR service

259 Operation
Tires and wheels
Tires and wheels
For safety reasons, only use tires and rims
which have been tested and approved by
Mercedes-Benz for use on SLR vehicles.
Contact an authorized Mercedes-Benz
Center for information on tested and
recommended rims and tires for summer
and winter operation. They can also offer
advice concerning tire service and
purchase.
Important guidelines

For the first 100 miles (160 km) avoid
high-speed cornering. Do not exceed a
speed of 125 mph (200 km/h).
1


Only use sets of tires and rims of the
same type and make.


Tires must be of the correct size for the
rim.


Regularly check the tires and rims for
damage. Dented or bent rims can
cause tire inflation pressure loss and
damage to the tire beads.


If vehicle is heavily loaded, check tire
inflation pressure and correct as
required.
Warning!
G
Replace rims or tires with the same designa-
tion, manufacturer and type as shown on the
original part. Contact an authorized
Mercedes-Benz Center for further informa-
tion. If incorrectly sized rims and tires are
mounted:

The wheel brakes or suspension
components can be damaged.


The operating clearance of the wheels
and the tires may no longer be correct.
Warning!
G
Worn, old tires can cause accidents. If the
tire tread is badly worn, or if the tires have
sustained damage, replace them.
Have worn or damaged tires replaced in
pairs (front pair or rear pair) an make sure
the tires rotate in the direction specified
(page 262). Otherwise, the driving stabili-
ty of the vehicle will be adversely affected,
especially when driving at high speeds.
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 recom-
mended by Mercedes-Benz, since previous
damage cannot always be recognized on re-
treads. The operating safety of the vehicle
cannot be assured when such tires are used.
!
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.
1Please always drive carefully and obey applicable
speed limits.

261 Operation
Tires and wheels
Life of tire
The service life of a tire is dependent upon
varying factors including but not limited to:

Driving style


Tire inflation pressure


Distance driven
Tread depth
Do not allow your tires to wear down too
far. Adhesion properties on wet roads are
sharply reduced at tread depths of less
than 1/8in (3 mm).
Treadwear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and
become visible at a tread depth of approximately
1/16in (1.6 mm), at which
point the tire is considered worn and
should be replaced.
Recommended minimum tire tread depth:


Summer tires
1/8in (3 mm)


Winter tires
1/6in (4 mm)
1TWI (T
read W
ear I
ndicator)
The treadwear indicator appears as a solid
band across the tread.
Warning!
G
Tires should be replaced after 6 years,
regardless of the remaining tread.
Warning!
G
Although the applicable federal motor safety
laws consider a tire to be worn when the
treadwear indicators (TWI) become visible at
approximately
1/16in (1.6 mm), we recom-
mend that you do not allow your tires to
wear down to that level. As tread depth
approaches
1/8in (3 mm), the adhesion
properties on a wet road are sharply
reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction varies
widely.

278 OperationTires and wheelsRim diameter
The rim diameter4 (
page 277) is the
diameter of the bead seat, not the
diameter of the rim edge. Rim diameter is
indicated in inches (in).
Tire load rating
The tire load rating5 (page 277) is a
numerical code associated with the
maximum load a tire can support.
For example, a load rating of 91 corre-
sponds to a maximum load of 1356 lb
(615 kg) the tire is designed to support.
See also “Maximum tire load”
(
page 282) where the maximum load as-
sociated with the load index is indicated in
kilograms and lb.For additional information on tire load
rating, see “Load identification”
(
page 280).
Warning!
G
The tire load rating must always be at least
half of the GAWR (
page 287) of your
vehicle. Otherwise tire failure may be the re-
sult which may cause an accident and/or
serious injury to you or others.
Always replace rims and tires with the same
designation, manufacturer and type as
shown on the original part.
Warning!
G
Do not overload the tires by exceeding the
specified load limit or vehicle capacity
weight as indicated on the Tire and Loading
Information placard located on the driver’s
door B-pillar. Overloading the tires can over-
heat them, possibly causing a blowout.
Overloading the tires can also result in han-
dling or steering problems, or brake failure.
i
Tire load rating5 (
page 277) and tire
speed rating6 (
page 277) are also referred
to as “service description”.

279 Operation
Tires and wheels
Tire speed rating
The tire speed rating6 (
page 277)
indicates the approved maximum speed
for the tire.Summer tires


At the tire manufacturer’s option, any
tire with a speed capability above
149 mph (240 km/h) can include a
“ZR” in the size designation (for exam-
ple: 245/40 ZR18). To determine the
maximum speed capability of the tire,
the service description for the tire must
be referred to. The service description is comprised of the tire load rating5
(
page 277) and the tire speed
rating6 (
page 277).
If your tire includes “ZR” in the size
designation and no service
description5 and6 (
page 277) is
given, the tire manufacturer must be
consulted for the maximum speed
capability.
If a service description5 and6
(
page 277) is given, the speed capa-
bility is limited by the speed symbol in
the service description.
Example: 245/40 ZR18 97Y.
In this example, “97Y” is the service
description. The letter “Y” designates
the speed rating and the speed capabil-
ity of the tire is limited to 186 mph
(300 km/h).
Warning!
G
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
personal injury and possible death, for you
and for others.i
Tire load rating5 (
page 277) and tire
speed rating6 (
page 277) are also referred
to as “service description”.
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)
(Y)
above 186 mph (300 km/h)
ZR
above 149 mph (240 km/h)

280 OperationTires and wheels

Any tire with a speed capability above
186 mph (300 km/h) must include a
“ZR” in the size designation AND the
service description must be placed in
parenthesis.
Example: 275/40 ZR 18 (99Y).
The “(Y)” speed rating in parenthesis
designates the maximum speed capa-
bility of the tire as being above
186 mph (300 km/h). Consult the tire
manufacturer for the actual maximum
permissible speed of the tire.All-season and winter tires
Load identification
1Load identification
In addition to tire load rating, special load
identification1 may be molded into the
tire sidewall following the letter designat-
ing the tire speed rating (
page 277).
Index
Speed rating
QM+S
1
1or M+S.for winter tires
up to 100 mph (160 km/h)
TM+S
1
up to 118 mph (190 km/h)
HM+S
1
up to 130 mph (210 km/h)
VM+S
1
up to 149 mph (240 km/h)
i
Not all M+S rated tires provide special win-
ter performance. Make sure the tires you use
show M+S and the mountain/snowflake.
marking on the tire sidewall. These tires meet
specific snow traction performance require-
ments of the Rubber Manufacturers Association
(RMA) and the Rubber Association of Canada
(RAC) and have been designed specifically for
use in snow conditions.
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

284 OperationTires and wheelsUniform Tire Quality Grading Standards (U.S. vehicles)
Tire manufacturers are required to grade
tires based on three performance
factors: treadwear, traction and
temperature resistance.
1Treadwear
2Traction
3Temperature resistanceQuality grades can be found, where appli-
cable, on the tire sidewall between tread
shoulder and maximum section width. For
example:
All passenger car tires must conform to
federal safety requirements in addition to
these grades.Treadwear
The treadwear grade is a comparative rat-
ing based on the wear rate of the tire when
tested under controlled conditions on a
specified government test course. For ex-
ample, a tire graded 150 would wear one
and one-half (1
1/2) 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.
i
For illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.
Treadwear
Traction
Temperature
200
AA
A

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.