
when adjusting the tire pressure
(Y page 366).
i
The actual values for tires are vehicle-
specific
and may deviate from the values in
the illustration. Checking the tire pressures
Important safety notes Observe the notes on tire pressure
(Y page 366).
Information on air pressure for the tires on
your vehicle can be found:
R
on the vehicle's Tire and Loading
Information placard on the B-pillar
(Y page 373)
R on the tire pressure label on the fuel filler
flap ( Y page 170)
R in the "Tire pressure" section
R under "Tire pressure"
(Y page 366)
Checking tire pressures manually To determine and set the correct tire
pressure, proceed as follows:
X
Remove the valve cap of the tire that is to
be checked.
X Press the tire pressure gauge securely onto
the valve.
X Read the tire pressure and compare it with
the recommended value on the Tire and
Loading Information placard
(Y page 366).
X If the tire pressure is too low, increase it to
the recommended value.
X If the tire pressure is too high, release air
by
pressing down the metal pin in the valve.
Use the tip of a pen, for example. Then,
check the tire pressure again using the tire
pressure gauge.
X Screw the valve cap onto the valve.
X Repeat these steps for the other tires. Tire pressure loss warning system
(Canada only)
Important safety notes While the vehicle is in motion, the tire
pressure loss warning system monitors the
set
tire pressure using the rotational speed of
the wheels. This enables the system to detect
significant pressure loss in a tire. If the speed
of rotation of a wheel changes as a result of
a loss of pressure, a corresponding warning
message will appear in the multifunction
display.
The tire pressure warning system does not
warn you of an incorrectly set tire pressure.
Observe the notes on the recommended tire
pressure ( Y page 366).
The tire pressure loss warning system does
not replace the need to regularly check your
vehicle's tire pressures, since an even loss of
pressure on several tires at the same time
cannot be detected by the tire pressure loss
warning system.
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 function of the tire pressure loss warning
system is limited or delayed if:
R snow chains are mounted to your vehicle's
tires.
R road conditions are wintry.
R you are driving on sand or gravel.
R you adopt a very sporty driving style
(cornering at high speeds or driving with
high rates of acceleration).
R you are driving with a heavy load (in the
vehicle or on the roof). Tire pressure
369
Wheels and tires Z

Restarting the tire pressure loss
warning system
Restart the tire pressure loss warning system
if you have:
R
changed the tire pressure
R changed the wheels or tires
R mounted new wheels or tires
X Before restarting, make sure that the tire
pressures are set properly on all four tires
for the respective operating conditions.
The recommended tire pressures can be
found on the Tire and Loading Information
placard on the B-pillar
on the driver's side
or the tire pressure table on the fuel filler
flap. The tire pressure loss warning system
can only give reliable warnings if you have
set the correct tire pressure. If an incorrect
tire pressure is set, these incorrect values
will be monitored.
X Also observe the notes in the section on tire
pressures ( Y page 366).
X Make sure that the SmartKey is in
position 2 (Y
page 153) in the ignition lock.
X Press = or ; on the steering wheel
to select the Serv.Serv. menu.
X Press the 9 or : button to select
Tire Pressure.
X Press the a button.
The message appears in the multifunction
display.
If you wish to confirm the restart:
X Press the a button.
The Tire Pressure Now OK? message
appears in the multifunction display.
X Press the 9 or : button to select
Yes.
X Press the a button.
The Run Flat Indicator Restarted
message appears in the multifunction
display.
After a teach-in period, the tire pressure
loss warning system will monitor the set
tire pressures of all four tires. If you wish to cancel the restart:
X
Press the % button.
or
X When the Tire Pressure Now OK?
message appears, press the 9
or : button to select Cancel.
X Press the a button.
The tire pressure values stored at the last
restart will continue to be monitored. Tire pressure monitor
Important safety notes G
WARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure
recommended by the vehicle manufacturer
on the Tire and Loading Information placard
on the driver's door B-pillar or the tire
pressure label on the inside of the fuel filler
flap.
If your vehicle has tires of a different size
than the size indicated on the Tire and Loading
Information placard or the tire pressure label,
you should determine the proper tire pressure
for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring
system (TPMS) that illuminates a low tire
pressure telltale when one or more of your
tires are significantly underinflated.
Accordingly, when the low tire pressure
telltale illuminates, you should stop and check
your tires as soon as possible, and inflate
them to the proper pressure. Driving on a
significantly underinflated tire causes the tire
to overheat and can lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's
handling and stopping ability.
Please note that the TPMS is not a substitute
for proper tire maintenance, and it is the
driver's responsibility to maintain correct tire
pressure, even if underinflation has not 370
Tire pressure
Wheels and tires

To ensure that your vehicle does not exceed
the maximum permissible values (gross
vehicle 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.
All about wheels and tires
Uniform Tire Quality Grading
Standards
Overview of Tire Quality Grading
Standards Uniform Tire Quality Grading Standards are
U.S. government specifications. Their
purpose is to provide drivers with uniform
reliable
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.
Where applicable, the tire grading
information can be found on the tire sidewall
between the tread shoulder and maximum
tire width.
Example:
R Treadwear grade: 200
R Traction grade: AA
R Temperature grade: A All passenger car tires must conform to the
statutory safety requirements in addition to
these grades.
i
The 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,
however, and may depart significantly from
the norm, due to variations in driving habits,
service practices and differences in road
characteristics and climate conditions.
Traction G
WARNING
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.
! 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 a wet surface 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
surfaces.
You should pay special attention to road
conditions when temperatures are around
freezing point. All about wheels and tires
377Wheels and tires Z

Mercedes-Benz recommends a minimum
tread
depth of ã in (4 mm) on all four winter
tires. Observe the legally required minimum
tire tread depth (Y page 363). 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 appropriate care when driving.
Further information on winter tires (M+S
tires) (Y page 364).
Temperature G
WARNING
The temperature grade for this tire is
established for a tire that is properly inflated
and not overloaded. Excessive speed,
underinflation, 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. These represent the tire's
resistance to the generation of heat and its
ability to dissipate heat when tested under
controlled conditions 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. Tire labeling
Overview :
Uniform Tire Quality Grading Standard
(Y page 382)
; DOT, Tire Identification Number
(Y page 381)
= Maximum tire load ( Y page 381)
? Maximum tire pressure (Y page 368)
A Manufacturer
B Tire material ( Y page 382)
C Tire size designation, load-bearing
capacity and speed index
(Y page 378)
D Load index ( Y page 381)
E Tire name
The markings described above are on the tire
in addition to the tire name (sales
designation) and the manufacturer's name.
i Tire data is vehicle-specific and may
deviate from the data in the example.
Tire size designation, load-bearing
capacity and speed rating G
WARNING
Exceeding the stated tire load-bearing
capacity and the approved maximum speed
could
lead to tire damage or the tire bursting.
There is a risk of accident. 378
All about wheels and tires
Wheels and tires

Always observe the instructions and safety
notes in the "Mounting a wheel" section
(Y page 385).
The wear patterns on the front and rear tires
differ,
depending on the operating conditions.
Rotate the wheels before a clear wear pattern
has formed on the tires. Front tires typically
wear more on the shoulders and the rear tires
in the center.
If your vehicle's tire configuration allows, you
can rotate the wheels according to the
intervals in the tire manufacturer's warranty
book in your vehicle documents. If this is not
available, the tires should then be replaced
every 3,000 to 6,000 miles (5,000 to
10,000 km), or earlier if the tire wear requires
this. Do not change the direction of wheel
rotation.
Clean the contact surfaces of the wheel and
the brake disc thoroughly every time a wheel
is interchanged. Check the tire pressure and,
if necessary, restart the tire pressure loss
warning system or the tire pressure monitor. Direction of rotation
Tires with a specified direction of rotation
have
additional benefits, e.g. if there is a risk
of hydroplaning. You will only gain these
benefits if the correct direction of rotation is
maintained.
An arrow on the sidewall of the tire indicates
its correct direction of rotation. Storing wheels
Store
wheels that are not being used in a cool,
dry and preferably dark place. Protect the
tires from oil, grease, gasoline and diesel. Cleaning the wheels
G
WARNING
The water jet from a circular jet nozzle (dirt
blasters)
can cause invisible exterior damage to the tires or chassis components.
Components damaged in this way may fail
unexpectedly. There is a risk of an accident.
Do not use power washers with circular jet
nozzles to clean the vehicle. Have damaged
tires or chassis components replaced
immediately.
Mounting a wheel
Preparing the vehicle X
Park the vehicle on firm, non-slippery and
level ground.
X Apply the parking brake.
X Bring the front wheels into the straight-
ahead position.
X Shift the transmission to position P.
X Vehicles with AIRMATIC: make sure that
"normal" level is selected
(Y page 199).
X Switch off the engine.
X Vehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.
X Vehicles with KEYLESS-GO: open the
driver's door.
The on-board electronics have status 0,
which is the same as the SmartKey having
been removed.
X Vehicles with KEYLESS-GO: remove the
Start/Stop button from the ignition lock
(Y page 154).
X If included in the vehicle equipment, take
the tire-change tool kit out of the vehicle.
X Secure the vehicle to prevent it from rolling
away. Changing a wheel
385
Wheels and tires Z

Example
X
Make sure the foot of the jack is directly
beneath the jacking point.
X Turn crank A clockwise until jack ? sits
completely on jacking point = and the
base of the jack lies evenly on the ground.
X Turn crank A until the tire is raised a
maximum of 1.2 in (3 cm ) off the ground.
Removing a wheel !
AMG vehicles: during removal and
repositioning of the wheel, the wheel rim
can strike the ceramic-brake disc and
damage
it. Therefore, take precautions and
get a second person to assist you.
Alternatively, you can use a second
alignment bolt.
! Do not place wheel bolts in sand or on a
dirty surface. The bolt and wheel hub
threads could otherwise be damaged when
you screw them in. X
Unscrew the uppermost wheel bolt
completely.
X Screw alignment bolt : into the thread
instead of the wheel bolt.
X Unscrew the remaining wheel bolts fully.
X Remove the wheel.
Mounting a new wheel G
WARNING
Oiled or greased wheel bolts or damaged
wheel
bolts/hub threads can cause the wheel
bolts to come loose. As a result, you could
lose a wheel while driving. There is a risk of
accident.
Never oil or grease wheel bolts. In the event
of damage to the threads, contact a qualified
specialist workshop immediately. Have the
damaged wheel bolts or hub threads
replaced/renewed. Do not continue driving. G
WARNING
If you tighten the wheel bolts or wheel nuts
when the vehicle is raised, the jack could tip
over. There is a risk of injury.
Only tighten the wheel bolts or wheel nuts
when the vehicle is on the ground.
Always pay attention to the instructions and
safety notes in the "Changing a wheel"
section ( Y page 384).
Only
use wheel bolts that have been designed
for the wheel and the vehicle. For safety
reasons, Mercedes-Benz recommends that
you only use wheel bolts which have been
approved for Mercedes-Benz vehicles and the
respective wheel.
! AMG vehicles: during removal and
repositioning of the wheel, the wheel rim
can strike the ceramic-brake disc and
damage it. Therefore, take precautions and
get a second person to assist you.
Alternatively, you can use a second
alignment bolt. 388
Changing a wheel
Wheels and tires

!
To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt. Positioning a wheel (example: vehicle with
emergency spare wheel)
X
Clean the wheel and wheel hub contact
surfaces.
X Slide the wheel to be mounted onto the
alignment bolt and push it on.
X Tighten the wheel bolts until they are
finger-tight.
X Unscrew the alignment bolt.
X Tighten the last wheel bolt until it is finger-
tight.
X Vehicles with a collapsible spare
wheel: inflate the collapsible spare wheel
(Y page 400).
Only then lower the vehicle.
Lowering the vehicle G
WARNING
The wheels could work loose if the wheel nuts
and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed.
! Vehicles with a collapsible spare
wheel: before lowering the vehicle, inflate
the collapsible spare wheel with the tire
inflation compressor. The wheel rim could
otherwise be damaged. Tightening wheel bolts (example: vehicle with
emergency spare wheel)
X
Turn the crank of the jack counter-
clockwise until the vehicle is once again
standing firmly on the ground.
X Place the jack to one side.
X Tighten the wheel bolts evenly in a
crosswise pattern in the sequence
indicated ( :
to A). The tightening torque
must be 96 lb-ft (130 Nm).
X Turn the jack back to its initial position.
X Stow the jack and the rest of the vehicle
tools in the trunk again.
X AMG vehicles and vehicles with AMG
equipment:
insert the cover into the outer
sill.
X Check the tire pressure of the newly
mounted wheel and adjust it if necessary.
Observe the recommended tire pressure
(Y page 366).
i Vehicles with tire pressure monitor: all
wheels mounted must be equipped with
functioning sensors. Wheel and tire combinations
General notes
! For safety reasons, Mercedes-Benz
recommends that you only use tires and
wheels which have been approved by
Mercedes-Benz specifically for your
vehicle. Wheel and tire combinations
389
Wheels and tires Z

R18
Tires Alloy wheels
245/40 R18 97 H XL M+S
i RA: 8.5 J x 18 H2
Wheel offset: 1.89 in
(48 mm)Emergency spare wheel
Important safety notes
G
WARNING
The wheel or tire size as well as the tire type
of
the spare wheel or emergency spare wheel
and the wheel to be replaced may differ.
Mounting an emergency spare wheel may
severely impair the driving characteristics.
There is a risk of an accident.
To avoid hazardous situations:
R adapt your driving style accordingly and
drive carefully.
R never install more than one spare wheel or
emergency spare wheel that differs in size.
R only use a spare wheel or emergency spare
wheel of a different size briefly.
R do not switch ESP ®
off.
R have a spare wheel or emergency spare
wheel of a different size replaced at the
nearest qualified specialist workshop.
Observe that the wheel and tire dimensions
as well as the tire type must be correct.
When using an emergency spare wheel or
spare wheel of a different size, you must not
exceed the maximum speed of 50 mph
(80 km/h).
Snow chains must not be mounted on
emergency spare wheels. General notes
You should regularly check the pressure of
the
emergency spare wheel, particularly prior
to long trips, and correct the pressure as
necessary (Y page 366). The applicable value is found on the wheel or under "Technical
data" (
Y page 402).
An emergency spare wheel may also be
mounted against the direction of rotation.
Observe
the time restriction on use as well as
the speed limitation specified on the
emergency spare wheel.
Replace the tires after six years at the latest,
regardless of wear. This also applies to the
emergency spare wheel.
i When you are driving with the collapsible
spare wheel mounted, the tire pressure
loss warning system or the tire pressure
monitor cannot function reliably. Only
restart the tire pressure loss warning
system/the tire pressure monitor when the
damaged wheel has been replaced with a
new wheel.
Vehicles with tire pressure monitor:
after mounting an emergency spare wheel,
the system may still display the tire
pressure of the removed wheel for a few
minutes. The value displayed for the
mounted emergency spare wheel is not the
same as the current tire pressure of the
emergency spare wheel. 398
Emergency spare wheel
Wheels and tires