inflation pressure MERCEDES-BENZ C230 2007 W203 User Guide

290 Operation
Tires and wheels
Important notes on tire inflation
pressure
Tire temperature and tire inflation pressure
are also increased while driving, depending
on the driving speed and the tire load.
If you will be driving your vehicle at high
speeds of 100 mph (160km/h) or higher,
where it is legal and conditions allow,
consult the placard on the inside of the fuel
filler flap on how to adjust the cold tire
inflation pressure. If you do not adjust the
tire inflation pressure, excessive heat can
build up and result in sudden tire failure.Be sure to readjust the tire inflation
pressure for normal driving speeds. You
should wait until the tires are cold before
adjusting the tire inflation pressure.
Some vehicles may have supplemental tire
inflation pressure information for vehicle
loads less than the maximum loaded
vehicle condition. If such information is
provided, it can be found on the placard
located on the inside of the fuel filler flap.
Tire inflation pressure changes by approxi-
mately 1.5 psi (0.1 bar) per 18°F (10°C) of
air temperature change. Keep this in mind
when checking tire inflation pressure
where the temperature is different from
the outside temperature.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.
Warning!G
If the tire inflation pressure repeatedly
drops:

Check the tires for punctures from
foreign objects.

Check to see whether air is leaking from
the valves or from around the rim.
iDriving comfort may be reduced when the
tire inflation pressure is adjusted to the value for
speeds above 100 mph (160 km / h) as specified
on the placard located on the inside of the fuel
filler flap.

291 Operation
Tires and wheels
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 289). If necessary, add air to
achieve the recommended tire inflation
pressure.
Install the valve cap.
Repeat this procedure for each tire.Run Flat Indicator*
U.S. vehicles: The Run Flat Indicator is only
available in conjunction with the
MOExtended* system (
page 294).
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.
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 as indicated on the plac-
ard on the driver’s door B-pillar. Overloading
the tires can overheat them, possibly caus-
ing a blowout.
iIf you have overfilled the tire, release tire in-
flation 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.

292 Operation
Tires and wheels
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)
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.
iThe recommended tire inflation pressures
for your vehicle can be found on the tire placard
located on the driver’s door B-pillar
(
page 289). The tire inflation 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 more than
one 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.

293 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.
Switch on the ignition (page 32).
The standard display menu appears in
the multifunction display (
page 126).
Press buttonk orj repeatedly
until the following message appears in
the multifunction display:
Press the reset button in the
instrument cluster (
page 311).
The following message will appear in
the multifunction display:
Restart
Run Flat
Indicator?
Yes
Chancel
If you wish to confirm activation:
Press buttonæ.
The following message will appear in
the multifunction display:
Run Flat
Indicator
restarted
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
Restart
Run Flat
Indicator?
Yes
Chancel
disappears.
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.

294 Operation
Tires and wheels
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
characteristicsOverinflated 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
MOExtended system*
The MOExtended system allows you to
continue driving your vehicle even if there
is a total loss of pressure in one or more
tires.
You may only use the MOExtended system
in conjunction with the Run Flat Indicator*
(
page 291).
For information on driving in case of pres-
sure loss in one or more tires (emergency
mode), see the “Practical hints” section
(
page 382).
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.
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.

295 Operation
Tires and wheels
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 302)
2DOT, Tire Identification Number (TIN)
(
page 299)
3Maximum tire load (
page 301)
4Maximum tire inflation pressure
(
page 301)
5Manufacturer
6Tire ply material (
page 304)
7Tire size designation, load and speed
rating (
page 295)
8Load identification (
page 299)
9Tire nameTire size designation, load and speed
rating
1Tire width
2Aspect ratio in %
3Radial tire code
4Rim diameter
5Tire load rating
6Tire speed rating
iFor 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 403).
iFor illustration purposes only. Actual data
on tires is specific to each vehicle and may vary
from data shown in above illustration.

301 Operation
Tires and wheels
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 296).
For information on calculating total and
cargo load capacities (
page 286).
Maximum tire inflation pressure
1Maximum permissible tire inflation
pressure
This is the maximum permissible tire
inflation pressure for the tire.
iFor illustration purposes only. Actual data
on tires is 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 as indicated on the plac-
ard 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.
iFor illustration purposes only. Actual data
on tires is specific to each vehicle and may vary
from data shown in above illustration.

302 Operation
Tires and wheels
Always follow the recommended tire
inflation pressure (
page 289) for proper
tire inflation. Uniform 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
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.
iFor illustration purposes only. Actual data
on tires is specific to each vehicle and may vary
from data shown in above illustration.
TreadwearTractionTemperature
200AAA

304 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
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 one 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.
iFor illustration purposes only. Actual data
on tires is specific to each vehicle and may vary
from data shown in above illustration.

305 Operation
Tires and wheels
DOT (Department of Transportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross Axle Weight Rating)
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 B-pillar.
GVW (G
ross Vehicle Weight)
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 B-pillar.GVWR (G
ross 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
certification label located on the driver’s
door B-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 weight, 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.