inflation pressure MERCEDES-BENZ C55AMG 2006 W203 User Guide

317 Operation
Tires and wheels
Checking tire inflation pressure
Regularly check your tire inflation pressure
at least once a month.
Check and adjust the tire inflation
pressure when the tires are cold. The tires
can be considered cold if the vehicle has
been parked for at least three hours or
driven less than one mile (1.6 km).
If you check the tire inflation pressure
when the tires are warm (the vehicle has
been driven for several miles or sitting less
than three hours), the reading will be
approximately 4 psi (0.3 bar) higher than
the cold reading. This is normal. Do not let
air out to match the specified cold tire
inflation pressure. Otherwise, the tire will
be underinflated.Checking tire inflation pressure
manually
Follow the steps below to achieve correct
tire inflation pressure:
Remove the cap from the valve on one
tire.
Firmly press a tire gauge onto the
valve.
Read tire inflation pressure on tire
gauge and check against the recom-
mended tire inflation pressure on the
placard on the driver’s door B-pillar
(
page 315). If necessary, add air to
achieve the recommended tire inflation
pressure.
Warning!G
Follow recommended tire inflation pres-
sures.
Do not overinflate tires. Overinflating tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes,
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Do not overload the tires by exceeding the
specified load limit or vehicle capacity
weight as indicated on the placard on the
driver’s door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout.


318 Operation
Tires and wheels
Install the valve cap.
Repeat this procedure for each tire.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
restricted manner or with a delay if:

snow chains are mounted to the
vehicle

winter road conditions prevail 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)
i
If you have overfilled the tire, release
tire inflation pressure by pushing the
metal stem of the valve with e.g. a tip of
a pen. Then recheck the tire inflation
pressure with the tire gauge.Warning!G
When the multifunction display shows the
message
Tire pressure Check tires,
one or more of your tires is significantly un-
der-inflated. 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. Driving on a significantly under-in-
flated tire causes the tire to overheat and
can lead to tire failure. Under-inflation also
reduces fuel efficiency 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 recommended tire infla-
tion pressure as specified in the vehicle
placard and owner’s manual.


319 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 or, if available, the inside
of the fuel filler flap, make sure the tire
inflation pressure of all four tires is cor-
rect.
i
The recommended tire inflation pres-
sures for your vehicle can be found on
the tire placard located on the driver’s
door B-pillar (
page 315). The tire in-
flation pressures are not listed in the
owner’s manual.
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
regular checks of the tire inflation pressures
since a gradual pressure loss in all four tires
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.

320 Operation
Tires and wheels
Switch on the ignition (page 33).
The standard display menu appears in
the multifunction display (
page 130).
Press buttonk orj repeatedly
until the following message appears in
the multifunction display:
Run Flat Indicator
active
Reactivation possible: +
Press buttonæ.
The following message will appear in
the multifunction display:
Tire pres. OK now?
If you wish to confirm activation:
Press buttonæ.
The following message will appear in
the multifunction display:
Run Flat Indicator
Reactivated
After a certain “learning phase”, the Run
Flat Indicator checks the set pressure
values for all four tires.
If you wish to cancel activation:
Press buttonç.
or
Wait until the message
Tire pres. OK now?
disappears.Potential problems associated with
underinflated and overinflated tires
Underinflated tires
Underinflated tires can:

cause excessive and uneven tire wear

adversely affect fuel economy

lead to tire failure from being
overheated

adversely affect handling
characteristics
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
according to the incorrect value.
Warning!G
Follow recommended tire inflation pres-
sures.
Do not underinflate tires. Underinflated tires
wear excessively and / or unevenly,
adversely affect handling and fuel economy,
and are more likely to fail from being
overheated.

321 Operation
Tires and wheels
Overinflated tires
Overinflated tires can:

adversely affect handling
characteristics

cause uneven tire wear

be more prone to damage from road
hazards

adversely affect ride comfort

increase stopping distance
Tire labeling
Besides tire name (sales designation) and
manufacturer name, a number of markings
can be found on a tire.
Following are some explanations for the
markings on your vehicle’s tires:1Uniform Quality Grading Standards
(
page 329)
2DOT, Tire Identification Number (TIN)
(
page 326)
3Maximum tire load (
page 327)
4Maximum tire inflation pressure
(
page 328)
5Manufacturer
6Tire ply material (
page 331)
7Tire size designation, load and speed
rating (
page 322)
8Load identification (
page 325)
9Tire name
Warning!G
Follow recommended tire inflation
pressures.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride
comfort, wear unevenly, increase stopping
distance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road
debris, potholes etc.
i
For illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
For more information, see “Rims and
Tires” (
page 429).

328 Operation
Tires and wheels
For more information on tire load rating
(
page 323).
For information on calculating total and
cargo load capacities (
page 311).
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 315) for proper
tire inflation. Warning!G
Do not overload the tires by exceeding the
specified load limit or vehicle capacity
weight as indicated on the placard located
on the driver’s door B-pillar. Overloading the
tires can overheat them, possibly causing a
blowout. Overloading the tires can also
result in handling or steering problems, or
brake failure.
i
For illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
Warning!G
Never exceed the max. tire inflation
pressure. Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and / or unevenly, adverse-
ly affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride com-
fort, wear unevenly, increase stopping dis-
tance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road de-
bris, potholes etc.

331 Operation
Tires and wheels
Tire 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
bar.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 kilopascal (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 one mile (1.6 km).
i
For illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.

333 Operation
Tires and wheels
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 (P
ounds per square inch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
Recommended tire inflation pressure
listed on placard located on driver’s door
B-pillar for normal driving conditions.
Provides best handling, tread life and
riding comfort.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 (Tire Identification Number)
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”.

335 Operation
Tires and wheels
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 a
front-to-rear rotation pattern that will
maintain the intended rotation (spinning)
direction of the tire (
page 308).
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 308).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
Thoroughly 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 380) and
(
page 404).
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.
Warning!G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
80 lb-ft (110 Nm).
Only use genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.

364 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Run Flat Indicator
inactive

The Run Flat Indicator* is malfunc-
tioning.Have the Run Flat Indicator* checked by an
authorized Mercedes-Benz Center.
Check tires
Then reactivate
Run Flat Indicator

There was a warning message about
a loss in tire inflation pressure and
the Run Flat Indicator* has not been
reactivated yet.Make sure that the correct tire inflation pressure
is set for each tire.
Then reactivate the Run Flat Indicator*.
Run Flat Indicator
unavailable

The Run Flat Indicator* has been
switched off due to an error.Have the Run Flat Indicator* checked by an
authorized Mercedes-Benz Center.
Tire pressure
Check tires

The Run Flat Indicator* indicates
that the pressure is too low in one or
more tires.Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers. Observe
the traffic situation around you.
Check and adjust the tire inflation pressure as
required (
page 317).
If necessary, change the wheel (page 404).
Reactivate the Run Flat Indicator* after adjusting
the tire inflation pressure values (
page 319).
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause exces-
sive heat build-up and possibly a fire.