The tire pressure monitor is not able to warn
you of a sudden loss of pressure, e.g. if the
tire is penetrated by a foreign object. In the
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering maneuvers.
The tire pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat-
ing pressure loss or a malfunction. Whether
the warning lamp flashes or lights up indi-
cates whether a tire pressure is too low or the
tire pressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, the
tire pressure on one or more tires is signif- icantly too low. The tire pressure monitor is
not malfunctioning.
Rif the warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(
Ypage 318).
It may take up to ten minutes for a malfunc-
tion of the tire pressure monitor to be indica-
ted. A malfunction will be indicated by the tire
pressure warning lamp flashing for approx-
imately one minute and then remaining lit.
When the malfunction has been rectified, the
tire pressure warning lamp goes out after a
few minutes of driving.
The tire pressure values indicated by the on-
board computer may differ from those meas-
ured at a gas station with a pressure gage.
The tire pressures shown by the on-board
computer refer to those measured at sea
level. At high altitudes, the tire pressure val-
ues indicated by a pressure gage are higher
than those shown by the on-board computer.
In this case, do not reduce the tire pressures.
The operation of the tire pressure monitor can
be affected by interference from radio trans-
mitting equipment (e.g. radio headphones,
two-way radios) that may be being operated
in or near the vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in position
2 in the ignition lock (
Ypage 165).
XPress the =or; button on the steer-
ing wheel to select the Service
menu.
XPress the9or: button to select
Tire Pressure
.
XPress the abutton.
The current tire pressure of each tire is
shown in the multifunction display.
If the vehicle has been parked for longer than
20 minutes, the Tire pressure will be
displayed after driving a few
minutesmessage appears.
After a teach-in process, the tire pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tire pressure value to the individual
wheels is not possible, the Tire Pressure
Monitor Activedisplay message is shown
instead of the tire pressure display. The tire
pressures are already being monitored.
iIf an emergency spare wheel is mounted,
the system may continue to show the tire
pressure of the wheel that has been
removed for a few minutes. If this occurs,
note that the value displayed for the posi-
tion where the spare wheel is mounted is
not the same as the current tire pressure of
the emergency spare wheel.
Tire pressure monitor warning mes-
sages
If the tire pressure monitor detects a pressure loss in one or more tires, a warning message
is shown in the multifunction display and the
yellow tire pressure monitor warning lamp
comes on.
RIf the Please Correct Tire Pressure
message appears in the multifunction dis-
play, the tire pressure in at least one tire is
414Tire pressure
Wheels and tires
too low and must be corrected at the next
opportunity.
RIf theCheckTiresmessage appears in the
multifunction display, the tire pressure in
one or more tires has dropped significantly
and the tires must be checked.
RIf the Warning Tire Malfunctionmes-
sage appears in the multifunction display,
the tire pressure in one or more tires has
dropped suddenly and the tires must be
checked.
iIf the wheel positions on the vehicle are
rotated, the tire pressures may be dis-
played for the wrong positions for a short
time. This is rectified after a few minutes of
driving, and the tire pressures are displayed
for the correct positions.
Restarting the tire pressure monitor
When you restart the tire pressure monitor, all
existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tire pressures as the refer-
ence values for monitoring. In most cases, the tire pressure monitor will automatically
detect the new reference values after you
have changed the tire pressure. However, you
can also define reference values manually as
described here. The tire pressure monitor
then monitors the new tire pressure values.
XSet the tire pressure to the value recom-
mended for the corresponding driving sit-
uation on the Tire and Loading Information
placard on the driver's side
B-pillar (
Ypage 408).
Additional tire pressure values for different
loads can also be found on the tire pressure table on the inside of the fuel filler flap
(
Ypage 408).
XMake sure that the tire pressure is correct
on all four wheels.
XMake sure that the SmartKey is in position2 in the ignition lock.
XPress the =or; button on the steer-
ing wheel to select the Service
menu.
XPress the9or: button to select
Tire Pressure
.
XPress the abutton.
The multifunction display shows the cur-
rent tire pressure for the individual tires or
the Tire
pressurewillbedisplayed
after driving a few minutesmes-
sage.
XPress the :button.
The Use Current Pressures as New
Reference Valuesmessage appears in
the multifunction display.
If you wish to confirm the restart:
XPress the abutton.
The Tire
PressureMonitorRestarted
message appears in the multifunction dis-
play.
After driving for a few minutes, the system
checks whether the current tire pressures
are within the specified range. The new tire
pressures are then accepted as reference
values and monitored.
If you wish to cancel the restart:
XPress the %button.
The tire pressure values stored at the last
restart will continue to be monitored.
Radio type approval for the tire pres-
sure monitor
CountryRadio type approval number
USAFCC ID: MRXMW2433A
FCC ID: MRXGG4
FCC ID: MRXMC34MA4
CanadaIC: 2546A-MW2433A
IC: 2546A-GG4
IC: 2546A-MC34MA4
Tire pressure415
Wheels and tires
Z
Loading the vehicle
Instruction labels for tires and loads
GWARNING
Overloaded tires can overheat, causing a
blowout. Overloaded tires can also impair the steering and driving characteristics and lead
to brake failure. There is a risk of accident.
Observe the load rating of the tires. The load
rating must be at least half of the GAWR of
your vehicle. Never overload the tires by
exceeding the maximum load.
Two instruction labels on your vehicle show
the maximum possible load.
(1) The Tire and Loading Information placard is on the B-pillar on the driver's side. The
Tire and Loading Information placard
shows the maximum permissible number
of occupants and the maximum permis-
sible vehicle load. It also contains details
of the tire sizes and corresponding pres-
sures for tires mounted at the factory.
(2) The vehicle identification plate is on the B-pillar on the driver's side. The vehicle
identification plate informs you of the
gross vehicle weight rating. It is made up
of the vehicle weight, all vehicle occu-
pants, the fuel and the cargo. You can
also find information about the maximum
gross axle weight rating on the front and
rear axle.
The maximum gross axle weight rating is
the maximum weight that can be carried
by one axle (front or rear axle). Never
exceed the maximum load or the maxi-
mum gross axle weight rating for the
front or rear axle.
:B-pillar, driver's side
Maximum permissible gross vehicle
weight rating
XSpecification for maximum gross vehicle
weight :is listed in the Tire and Loading
Information placard: "The combined weight of occupants and cargo should never
exceed XXX kilograms or XXX lbs."
The gross weight of all vehicle occupants,
load and luggage must not exceed the speci-
fied value.
iThe specifications shown on the Tire and
Loading Information placard in the illustra-
tion are examples. The maximum permis-
sible gross vehicle weight rating is vehicle- specific and may differ from that in the
illustration. You can find the valid maximum
416Loading the vehicle
Wheels and tires
permissible gross vehicle weight rating for
your vehicle on the Tire and Loading Infor-
mation placard.
Number of seats
Maximum number of seats:indicates the
maximum number of occupants allowed to
travel in the vehicle. This information can be
found on the Tire and Loading Information
placard.
iThe specifications shown on the Tire and
Loading Information placard in the illustra-
tion are examples. The number of seats is
vehicle-specific and can differ from the
details shown. The number of seats in your vehicle can be found on the Tire and Load-
ing Information placard.
Determining the correct load limit
Step-by-step instructions
The following steps have been developed as
required of all manufacturers under Title 49,
Code of U.S. Federal Regulations, Part 575
pursuant to the "National Traffic and Motor
Vehicle Safety Act of 1966".
XStep 1: Locate the statement "The com-
bined weight of occupants and cargo
should never exceed XXX kg or XXX lbs." on your vehicle’s Tire and Loading Information
placard.
XStep 2:
Determine the combined weight of
the driver and passengers that will be riding
in your vehicle.
XStep 3: Subtract the combined weight of
the driver and passengers from XXX kilo-
grams or XXX lbs.
XStep 4: The resulting figure equals the
available amount of cargo and luggage load capacity. For example, if the "XXX" amount
equals 1400 lbs and there will be five
150-lb passengers in your vehicle, the
amount of available cargo and luggage load
capacity is 650 lbs (1400 - 750 (5 x 150) =
650 lbs).
XStep 5: Determine the combined weight of
luggage and cargo being loaded on the
vehicle. That weight may not safely exceed the available cargo and luggage load capa-
city calculated in step 4.
Loading the vehicle417
Wheels and tires
Z
Example: steps 1 to 3
The following table shows examples on how to calculate total and cargo load capacities with
varying seating configurations and number and size of occupants. The following examples use
a load limit of 1500 lbs (680 kg).This is for illustration purposes only. Make sure you are
using the actual load limit for your vehicle stated on your vehicle's Tire and Loading Information
placard (
Ypage 416).
The greater the combined weight of the occupants, the lower the maximum luggage load.
Additional information when towing a trailer (
Ypage 264).
Step 1
Example 1Example 2Example 3
Combined maximum
weight of occupants
and cargo (data from
the Tire and Loading
Information placard)1500 lbs (680 kg)1500 lbs (680 kg)1500 lbs (680 kg)
Step 2
Example 1Example 2Example 3
Number of people in
the vehicle (driver
and occupants)531
Distribution of the
occupantsFront: 2
Rear: 3Front: 1
Rear: 2Front: 1
Weight of the occu-
pantsOccupant 1: 150 lbs
(68 kg)
Occupant 2: 180 lbs
(82 kg)
Occupant 3: 160 lbs (73 kg)
Occupant 4: 140 lbs
(63 kg)
Occupant 5: 120 lbs
(54 kg)Occupant 1: 200 lbs
(91 kg)
Occupant 2: 190 lbs
(86 kg)
Occupant 3: 150 lbs(68 kg)Occupant 1: 150 lbs
(68 kg)
Gross weight of all
occupants750 lbs (340 kg)540 lbs (245 kg)150 lbs (68 kg)
418Loading the vehicle
Wheels and tires
Step 3
Example 1Example 2Example 3
Permissible load
(maximum gross vehi-
cle weight rating from
the Tire and Loading
Information placard
minus the gross
weight of all occu-
pants)1500 lbs (680 kg)Ò
750 lbs (340 kg) =
750 lbs (340 kg)1500 lbs (680 kg) Ò
540 lbs (245 kg)
=960 lbs (435 kg)1500 lbs (680 kg) Ò
150 lbs (68 kg) =
1350 lbs (612 kg)
Vehicle identification plate
Even if you have calculated the total cargo
carefully, you should still make sure that the
gross vehicle weight rating and the gross axle
weight rating are not exceeded. Details can
be found on the vehicle identification plate on
the B-pillar on the driver's side of the vehicle
(
Ypage 416).
Permissible Gross Vehicle Weight Rating
(GVWR): the gross weight of the vehicle, all
passengers, load and trailer load/noseweight
(if applicable) must not exceed the permissi-
ble gross vehicle weight.
Gross Axle Weight Rating (GAWR): the
maximum permissible weight that can be car-
ried by one axle (front or rear axle).
To ensure that your vehicle does not exceed
the maximum permissible values (gross vehi-
cle weight and maximum gross axle weight
rating), have your loaded vehicle (including
driver, occupants, cargo, and full trailer load if
applicable) weighed on a suitable vehicle
weighbridge.
Trailer load/noseweight
The trailer load/noseweight affects the gross
weight of the vehicle. If a trailer is attached,
the trailer load/noseweight is included in the
load along with occupants and luggage. The
trailer load/noseweight is usually approx-
imately 8% of the gross weight of the trailer
and its cargo.
All about wheels and tires
Uniform Tire Quality Grading Stand-
ards
Overview of Tire Quality Grading Stand-
ards
Uniform Tire Quality Grading Standards are
U.S. government specifications. Their pur-
pose is to provide drivers with uniform relia-
ble information on tire performance data. Tire
manufacturers have to grade tires using three
performance factors: :tread wear grade, ;
traction grade and =temperature grade.
These regulations do not apply to Canada.
Nevertheless, all tires sold in North America
are provided with the corresponding quality
grading markings on the sidewall of the tire.
Quality grades can be found, where applica-
ble, on the tire sidewall between tread shoul-
der and maximum section width.
All about wheels and tires419
Wheels and tires
Z
Example:
RTreadwear grade:200
RTraction grade:AA
RTemperature grade: A
All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
iThe actual values for tires are vehicle-
specific and may deviate from the values in
the illustration.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
U.S. government course. For example, a tire
graded 150 would wear one and one-half
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, how-
ever, and may depart significantly from the
norm due to variations in driving habits, ser-
vice practices and differences in road char-
acteristics and climate.
Traction
GWARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction char-
acteristics.
!Avoid wheelspin. This can lead to damage
to the drive train.
The traction grades – from highest to lowest –
are AA, A, B and C. Those grades represent
the tire's ability to stop on wet pavement as
measured under controlled conditions on
specified government test surfaces of asphalt
and concrete. A tire marked C may have poor
traction performance. The safe speed on a wet, snow covered or icy
road is always lower than on dry road surfa-
ces.
You should pay special attention to road con-
ditions when temperatures are around freez-
ing point.
Mercedes-Benz recommends a minimum
tread depth of
ãin (4 mm) on all four winter
tires. Observe the legally required minimum
tire tread depth (
Ypage 405). Winter tires can
reduce the braking distance on snow-covered
surfaces in comparison with summer tires.
The braking distance is still much further than
on surfaces that are not icy or covered with
snow. Take appropri ate ca
re when driving.
Further information on winter tires (M+S
tires) (
Ypage 406).
Temperature
GWARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and
not overloaded. Excessive speed, underinfla-
tion, or excessive loading, either separately or
in combination, can cause excessive heat
build-up and possible tire failure.
The temperature grades are A (the highest), B,
and C, representing the tire's resistance to
the generation of heat and its ability to dissi-
pate heat when tested under controlled con-
ditions on a specified indoor laboratory test
wheel. Sustained high temperature can cause
the material of the tire to degenerate and
reduce tire life, and excessive temperature
can lead to sudden tire failure. The grade C
corresponds to a level of performance which
all passenger car tires must meet under the
Federal Motor Vehicle Safety Standard No.
109. Grades B and A represent higher levels
of performance on the laboratory test wheel
than the minimum required by law.
420All about wheels an d tires
Wheels and tires
Tire labeling
Overview
:Uniform Tire Quality Grading Standards
(
Ypage 425)
;Department of Transportation, Tire Iden-
tification Number (
Ypage 424)
=Maximum load rating (Ypage 423)
?Maximum tire pressures (Ypage 411)
AManufacturer
BTire material (Ypage 424)
CTire size designation, load-bearing capa-
city and speed rating (
Ypage 421)
DLoad index (Ypage 423)
ETire name
The markings described above are on the tire
in addition to the tire name (sales designa-
tion) and the manufacturer's name.
iTire data is vehicle-specific and may devi-
ate from the data in the example.
Tire size designation, load-bearing
capacity and speed rating
GWARNING
Exceeding the stated tire load-bearing capa-
city and the approved maximum speed could
lead to tire damage or the tire bursting. There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the
tire load rating and speed rating required for
your vehicle.
:Tire width
;Nominal aspect ratio in %
=Tire code
?Rim diameter
ALoad bearing index
BSpeed rating
General: depending on the manufacturer's
standards, the size imprinted in the tire wall
may not contain any letters or may contain
one letter that precedes the size description.
If there is no letter preceding the size descrip-
tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S.
manufacturing standards.
If "LT" precedes the size description: these
are light truck tires according to U.S. manu-
facturing standards.
If "T" precedes the size description: compactemergency wheels with high tire pressure
that are only designed for temporary use in an
emergency.
Tire width: tire width:shows the nominal
tire width in millimeters.
Height-width ratio: aspect ratio;is the
size ratio between the tire height and tire
width and is shown in percent. The aspect
All about wheels an d tires421
Wheels and tires
Z