2008 MERCEDES-BENZ S550 4MATIC card

564 Operation
Tires and wheels
Switch on the ignition (page 344).
Press( or& to select the menu
“Service”.
Press$ or% to select “Tire
pressure”.
Press#.
You will see

the current inflation pressures for
each tire
or

the message
“Tire pressures
displayed after driving
a few minutes”
appear in the multifunction display.
Press%.
The message
“Use current pressure
values as new
reference values
To confirm press "OK"”
appears in the multifunction display.
Press#.
The message
“Tire pressure monitor
restarted”
appears in the multifunction display.
After a few minutes driving, the current
tire inflation pressure values are ac-
cepted as reference values and then
monitored.
If you wish to cancel activation:
PressL.
or
Press$ to exit menu screen.
iReactivate the TPMS after adjusting the tire
inflation pressure to the inflation pressure rec-
ommended for the vehicle operating condition.
Tire inflation pressure should only be adjusted
on cold tires. Observe the recommended tire in-
flation pressure on the Tire and Loading Informa-
tion placard on the driver’s door B-pillar
(
page 553). Some vehicles may have supple-
mental tire inflation pressure information for
driving at high speeds (
page 559) or for vehi-
cle loads less than the maximum loaded vehicle
condition. If such information is provided, it can
be found on the inside of the fuel filler flap
(
page 538).
iAfter wheel rotation or sensor replacement,
the vehicle must be parked for 20 minutes be-
fore attempting to reactivate the TPMS.
iThe menu overview can be found on
(
page 266).iWhen the wheel positions are changed on
the vehicle, it is possible that the air pressure is
temporarily displayed for the wrong position.
This will be corrected after driving for several
minutes, and the air pressure will be shown for
the correct position.


565 Operation
Tires and wheels
Run Flat Indicator (Canada only)
While the vehicle is being driven, the Run
Flat Indicator monitors the set tire inflation
pressures by evaluating each wheel’s rota-
tional speed. This allows the system to de-
tect a significant loss of pressure in a tire.
If a wheel’s rotational speed changes due
to falling tire inflation pressure, you will
see a corresponding warning message in
the multifunction display.
The Run Flat Indicator may function in a re-
stricted manner or with a delay if:

snow chains are mounted to the
vehicle

in presence of ice and snow

you are driving on a loose surface (e.g.
sand or gravel)

you are driving in a very sporty manner
(involving rapid acceleration or high
speeds in curves)
Warning!G
When the multifunction display shows the
message “Tire pressure Check tires”, one or
more of your tires is significantly under-in-
flated. You should stop and check your tires
as soon as possible, and inflate them to the
proper tire inflation pressure as indicated on
the vehicle’s tire information placard. Driv-
ing on a significantly underinflated tire caus-
es the tire to overheat and can lead to tire
failure. Underinflation also reduces fuel effi-
ciency and tire tread life, and may affect the
vehicle’s handling and stopping ability. Each
tire, including the spare, should be checked
monthly when cold and set to the tire infla-
tion pressure recommended by the vehicle
manufacturer on the vehicle placard or the
tire inflation pressure label.
Warning!G
The Run Flat Indicator does not provide a
warning for wrongly selected tire inflation
pressures. Always adjust tire inflation pres-
sure according to the placard on the driver’s
door B-pillar or fuel filler flap.
The Run Flat Indicator does not replace reg-
ular checks of the tire inflation pressures
since a gradual pressure loss in more than
one tire cannot be detected by the Run Flat
Indicator.
The Run Flat Indicator is not able to issue a
warning due to a sudden dramatic loss of
tire inflation pressure (e.g. tire blowout
caused by a foreign object). In this case
bring the vehicle to a halt by carefully apply-
ing the brakes and avoiding abrupt steering
maneuvers.

566 Operation
Tires and wheels
Reactivating the Run Flat Indicator
The tire inflation pressure monitor must be
reactivated in the following situations:

If you have changed the tire inflation
pressure

If you have replaced the wheels or tires

If you have installed new wheels or
tires
Using the tire placard on the driver’s
door B-pillar (
page 553) or, if avail-
able, the inside of the fuel filler flap
(
page 538), make sure the tire infla-
tion pressure of all four tires is correct.
Switch on the ignition (page 344).
Press( or& to select the menu
“Service”.
Press$ or% to select “Tire
pressure”.
Press#.
The message
“Run Flat Indicator
active
Restart possible with OK”
appears in the multifunction display.
Press#.
The message
“Tire pressure
now OK?”
appears in the multifunction display.If you wish to confirm activation:
Press$ or% to select “Yes”.
Press#.
The message
“Run Flat Indicator
restarted”
appears in the multifunction display.
After a certain “learning phase”, the Run
Flat Indicator checks the set pressure val-
ues for all four tires.
If you wish to cancel activation:
PressL.
or
When the message
“Tire pressure
now OK?”
appears in the multifunction display:
Press$ or% to select “Cancel”.
Press#.
Warning!G
The Run Flat Indicator can only warn you in
a reliable manner if you have set the correct
tire inflation pressures for each tire.
If an incorrect tire inflation pressure was
set, the system will monitor the pressure ac-
cording to the incorrect value.
iThe menu overview can be found on
(
page 266).

569 Operation
Tires and wheels
Tire width
The tire width1 (
page 568) indicates
the nominal tire width in mm.
Aspect ratio
The aspect ratio2 (
page 568) is the
dimensional relationship between tire
section height and section width and is
expressed in percentage. The aspect ratio
is arrived at by dividing section height by
section width.
Tire code
The tire code3 (
page 568) indicates
the tire construction type. The “R” stands
for radial tire type. Letter “D” means diag-
onal or bias ply construction; letter “B”
means belted-bias ply construction.
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 example: 245/40 ZR 18).
For additional information, see “Tire speed
rating” (
page 570).Rim diameter
The rim diameter4 (
page 568) 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 568) 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 1 356 lbs
(615 kg) the tire is designed to support.
See also “Maximum tire load”
(
page 573) where the maximum load as-
sociated with the load index is indicated in
kilograms and lbs.
Warning!G
The tire load rating must always be at least
half of the GAWR (
page 576) of your vehi-
cle. Otherwise, tire failure may be the result
which may cause an accident and/or seri-
ous personal 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 total load limit as indi-
cated on the Tire and Loading Information
placard located on the driver’s door B-pillar
(
page 553). Overloading the tires can
overheat them, possibly causing a blowout.
Overloading the tires can also result in han-
dling or steering problems, or brake failure.

573 Operation
Tires and wheels
The first two figures identify the week,
starting with “01” to represent the first full
week of the calendar year. The second two
figures represent the year.
For example, “3202” represents the 32nd
week of 2002.
Maximum tire load
1Maximum tire load rating
The maximum tire load is the maximum
weight the tires are designed to support.For more information on tire load rating
(
page 569).
For information on calculating total and
cargo load capacities (
page 555).
Maximum tire inflation pressure
1Maximum permissible tire inflation
pressure
This is the maximum permissible tire
inflation pressure for the tire.
Always follow the recommended tire
inflation pressure (
page 558) for proper
tire inflation. iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.
Warning!G
Do not overload the tires by exceeding the
specified load limit or total load limit as indi-
cated on the Tire and Loading Information
placard located on the driver’s door B-pillar
(
page 553). Overloading the tires can
overheat them, possibly causing a blowout.
Overloading the tires can also result in han-
dling or steering problems, or brake failure.
iFor illustration purposes only. Actual data
on tires are specific to each vehicle and may vary
from data shown in above illustration.

577 Operation
Tires and wheels
GVWR (Gross Vehicle Weight Rating)
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 certi-
fication label located on the driver’s door
B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kilopascals (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 lbs).
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 lbs (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.PSI (Pounds per square inch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
The recommended tire inflation pressure
for normal driving conditions is listed on
the Tire and Loading Information placard
located on the driver’s door B-pillar and
provides best handling, tread life and
riding comfort. If so equipped, supplemen-
tal information 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.

609 Practical hints
What to do if …?
Warning!G
Each tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recom-
mended by the vehicle manufacturer on the
vehicle placard or the tire inflation pressure
label. (If your vehicle has tires of a different
size than the size indicated on the vehicle
placard or the tire inflation pressure label,
you should determine the proper tire infla-
tion pressure for those tires).
As an added safety feature, your vehicle has
been equipped with a tire pressure monitor-
ing system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires is significantly under-inflated. Accord-
ingly, when the low tire pressure telltale illu-
minates, you should stop and check your
tires as soon as possible, and inflate them to
the proper pressure. Driving on a significant-
ly under-inflated tire causes the tire to over-
heat and can lead to tire failure.
Under-inflation also reduces fuel efficiency
and tire tread life, and may affect the vehi-
cle’s handling and stopping ability. Please
note that the TPMS is not a substitute for
proper tire maintenance, and it is the driv-
er’s responsibility to maintain correct tire
pressure, even if under-inflation has not
reached the level to trigger illumination of
the TPMS low tire pressure telltale.
USA only:
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate
when the system is not operating properly.
The TPMS malfunction indicator is com-
bined with the low tire pressure telltale.
When the system detects a malfunction, the
telltale will flash for approximately
one minute and then remain continuously
illuminated. This sequence will continue
upon subsequent vehicle start-ups as long
as the malfunction exists. When the mal-
function indicator is illuminated, the system
may not be able to detect or signal low tire
pressure as intended.TPMS malfunctions may occur for a variety
of reasons, including the installation of
replacement or alternate tires or wheels on
the vehicle that prevent the TPMS from
functioning properly. Always check the
TPMS malfunction telltale after replacing
one or more tires or wheels on your vehicle
to ensure that the replacement or alternate
tires and wheels allow the TPMS to continue
to function properly.

718 Technical data
Rims and tires
!Only use tires which have been tested and
approved by Mercedes-Benz. Tires approved by
Mercedes-Benz are developed to provide best
possible performance in conjunction with the
driving safety systems on your vehicle such as
ABS or ESP
®. Tires specially developed for your
vehicle and tested and approved by
Mercedes-Benz can be identified by finding the
following on the tire’s sidewall:

MO = Mercedes-Benz Original equipment
tires
S63AMG and S65AMG:
Does not apply to all approved tires on AMG
vehicles. For information on tested and
approved tires for AMG vehicles, contact an
authorized Mercedes-Benz Center.
Using tires other than those approved by
Mercedes-Benz may result in damage that is not
covered by the Mercedes-Benz Limited
Warranty.
!Using tires other than those approved by
Mercedes-Benz can have detrimental effects,
such as

poor handling characteristics

increased noise

increased fuel consumption
Moreover, tires and rims not approved by
Mercedes-Benz may, under load, exhibit dimen-
sional variations and different tire deformation
characteristics that could cause them to come
into contact with the vehicle body or axle parts.
Damage to the tires or the vehicle may be the
result.
iFurther information on tires and rims is
available at any authorized Mercedes-Benz
Center. A placard with the recommended tire in-
flation pressures is located on the driver’s door
B-pillar (
page 553). Some vehicles may have
supplemental tire inflation pressure information
for driving at high speeds (
page 559) or for ve-
hicle loads less than the maximum loaded
vehicle condition (
page 568). If such informa-
tion is provided, it can be found on the placard lo-
cated on the inside of the fuel filler flap. The tire inflation pressure should be checked
regularly and should only be adjusted on cold
tires. Follow tire manufacturer’s maintenance
recommendation included with vehicle.
iThe following pages also list the approved
wheel rim and tire sizes for equipping your vehi-
cles with winter tires. Winter tires are not avail-
able as standard or optional factory equipment,
but can be purchased from an authorized
Mercedes-Benz Center.
Depending on vehicle model and the standard or
optional factory-equipped wheel rim/tire config-
uration on your vehicle (Appearance Package,
Sport Package etc.), equipping your vehicle with
winter tires approved for your vehicle model may
also require the purchase of two or four wheel
rims of the recommended size for use with these
winter tires. Contact an authorized
Mercedes-Benz Center for more information.