2018 MERCEDES-BENZ G-CLASS tire size

Checking the tire pressures
Important safety notes
Observe the notes on tire pressure
(Ypage 260).
Information on air pressure for the tires on your
vehicle can be found:
Ron the vehicle's Tire and Loading Information
placard on the B-pillar
Rin the tire pressure table in the fuel filler flap
(Ypage 120)
Runder "Tire pressure" (Ypage 260)
Checking tire pressures manually
To determine and set the correct tire pressure,
proceed as follows:
XRemove the valve cap of the tire that is to be
checked.
XPress the tire pressure gage securely onto the
valve.
XRead the tire pressure and compare it to the
recommended value on the Tire and Loading
Information placard or the tire pressure table
(
Ypage 260).
XIf the tire pressure is too low, increase the tire
pressure to the recommended value.
XIf the tire pressure is too high, release air. To
do so, press down the metal pin in the valve,
using the tip of a pen for example. Then check
the tire pressure again using the tire pressure
checker.
XScrew the valve cap onto the valve.
XRepeat these steps for the other tires.
Tire pressure monitor
General notes
If a tire pressure monitor is installed, the vehi-
cle's wheels have sensors that monitor the tire
pressures in all four tires. The tire pressure mon-
itor warns you if the pressure drops in one or
more of the tires. The tire pressure monitor only
functions if the corresponding sensors are
installed in all wheels.
Information on tire pressures is displayed in the
multifunction display. After a few minutes of
driving, the current tire pressure of each wheel
is shown in the Serv.
menu.
Information on the message display can be
found in the "Checking the tire pressure elec-
tronically" section (
Ypage 264).
Important safety notes
GWARNING
Each tire, including the spare (if provided),
should be checked at least once a month
when cold and inflated to the pressure rec-
ommended 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 Infor-
mation 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 pres-
sure 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 underin-
flated 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 stop-
ping 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 unde rinf
lation has not
reached the level to trigger illumination of the
TPMS low tire pressure telltale.
USA only:
Tire pressure263
Wheels and tires
Z

Radio type approval for the tire pres-
sure monitor
CountryRadio type approval number
USAFCC ID: MRXGG4
FCC ID: MRXMC34MA4
CanadaIC: 2546A-GG4
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 occu-
pants and the maximum permissible vehicle
load. It also contains details of the tire sizes
and corresponding pressures for tires
mounted at the factory.
(2) The vehicle identification plate is on the B- pillar on the driver's side. The vehicle iden-
tification plate informs you of the gross
vehicle weight rating. It is made up of the
vehicle weight, all vehicle occupants, the
fuel and the cargo. You can also find infor-
mation 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). Do not exceed
the maximum gross vehicle we ight o
r the
maximum gross axle weight rating for the
front or rear axle.
:B-pillar, driver's side
Maximum permissible gross mass
XSpecification for maximum permissible
load :is listed on the Tire and Loading Infor-
mation placard: "The combined weight of
occupants and cargo should never exceed
XXX kilograms or XXX lbs."
The gross weight of all vehicle occupants, cargo,
luggage and trailer load/noseweight (if applica-
ble) must not exceed the specified value.
iThe specifications shown on the Tire and
Loading Information placard in the illustration are examples. The maximum permissible load
is vehicle-specific and may deviate from the
data shown here. The maximum permissible
load that applies for your vehicle can be found
on your vehicle's Tire and Loading Informa-
tion placard.
266Loading the vehicle
Wheels and tires

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 plac-
ard.
iThe specifications shown on the Tire and
Loading Information placard in the illustration
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 Loading 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 pur-
suant to the "National Traffic and Motor Vehicle
Safety Act of 1966".
XStep 1: Locate the statement "The combined
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 kilograms or
XXX lbs.
XStep 4: The resulting figure equals the avail-
able amount of cargo and luggage load capa-
city. Example: if the "XXX" amount equals
1400 lbs and there will be five 150 lbs pas-
sengers in your vehicle, the amount of avail-
able 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 vehi-
cle. That weight may not safely exceed the
available cargo and luggage load capacity cal- culated in step 4.
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 maximum
load of 1,500 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 266).
The greater the combined weight of the occupants, the lower the maximum luggage load.
Observe the additional information when towing a trailer (
Ypage 154).
Step 1
Example 1Example 2Example 3
Combined maximum
weight of occupants
and load (data from the
Tire and Loading Infor-
mation placard)1500 lbs (680 kg)1500 lbs (680 kg)1500 lbs (680 kg)
Loading the vehicle267
Wheels and tires
Z

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 dissipate
heat when tested under controlled conditions
on a specified indoor laboratory test wheel. Sus-
tained 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 of tire labeling
:Uniform Tire Quality Grading Standard
(Ypage 273)
;DOT, Tire Identification Number
(Ypage 272)
=Maximum tire load (Ypage 272)
?Manufacturer
AMaximum tire pressure (Ypage 262)
BTire material (Ypage 273)
CTire size designation, load-bearing capacity
and speed rating (Ypage 270)
DLoad index (Ypage 272)
ETire name The markings described above are on the tire in
addition to the tire name (sales designation) and
the manufacturer's name.
iTire data is vehicle-specific and may deviate
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
;Height-width ratio in percentage
=Tire code
?Rim diameter
ALoad bearing index
BSpeed rating
General: depending on the manufacturer's
standards, a letter is imprinted into the tire wall before 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: passenger
vehicle tires according to U.S. manufacturing
standards.
If "P" precedes the size description: light truck
tires according to U.S. manufacturing stand-
ards.
270All about wheels and tires
Wheels and tires

If "T" precedes the size description: these are
compact emergency spare wheels at high tire
pressure, to be used only temporarily in an
emergency.
Tire width:tire width:shows the nominal tire
width in millimeters.
Height-width ratio: height-width ratio;is the
ratio between tire height and tire width. The
aspect ratio is calculated by dividing the tire
width by the tire height. The resulting quotient is
given as a percentage.
Tire code: tire code=shows the tire type. "R"
represents radial tires; "D" represents diagonal
tires; "B" represents diagonal radial tires.
Optionally, tires with a maximum speed of over
149 mph (240 km/h) may have "ZR" in the size
description, depending on the manufacturer
(e.g. 245/40 ZR 18).
Rim diameter: rim diameter?is the diameter
of the bead seat, not the diameter of the rim
flange. The rim diameter is specified in
inches (in).
The load-bearing index: load-bearing indexA
(also load index), is a code that contains the
maximum load-bearing capacity of a tire.
Do not overload the tires by exceeding the
specified load limit. The maximum permissible
load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side (
Ypage 266).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can bear.
Further information on the maximum tire load in
kilograms and pounds (
Ypage 272).
For further information on the load bearing
index, see "Load index" (
Ypage 272).
Speed rating: speed ratingBspecifies the
approved maximum speed of the tire.
iTire data is vehicle-specific and may deviate
from the data in the example.
Regardless of the speed rating, always observe
the speed limits. Drive carefully and adapt your driving style to the traffic conditions.
iSince 2009, tires in Europe which corre-
spond to the noise limitations of Directive
ECE-R 117 show an >>S<< (Sound) mark. This
marking is in accordance with the type
approval number and is not connected to the
speed ra

ting. Summer tires
IndexSpeed rating
Qup to 100 mph (160 km/h)
Rup to 106 mph (170 km/h)
Sup to 112 mph (180 km/h)
Tup to 118 mph (190 km/h)
Hup to 130 mph (210 km/h)
Vup to 149 mph (240 km/h)
Wup to 168 mph (270 km/h)
Yup to 186 mph (300 km/h)
ZR...Yup to 186 mph (300 km/h)
ZR...(..Y)over 186 mph (300 km/h)
ZRover 149 mph (240 km/h)
ROptionally, tires with a maximum speed of
over 149 mph (240 km/h) may have "ZR" in
the size description, depending on the man-
ufacturer (e.g. 245/40 ZR18).
The service specification is made up of load-
bearing index
Aand speed rating B.
RIf the size description of your tire includes
"ZR" and there are no service specifications,
ask the tire manufacturer in order to find out
the maximum speed.
If a service specification is available, the max-
imum speed is limited according to the speed
rating in the service specification. Example:
245/40 ZR18 97 Y.In this example, "97 Y" is
the service specification. The letter "Y" rep-
resents the speed rating and the maximum
speed of the tire is limited to 186 mph
(300 km/h).
RThe size description for all tires with maxi-
mum speeds of over 186 mph (300 km/h)
must include "ZR", andthe service specifica-
tion must be given in parentheses. Example:
275/40 ZR 18 (99 Y). Speed rating "(Y)" indi-
cates that the maximum speed of the tire is
over 186 mph (300 km/h). Ask the tire man-
ufacturer about the maximum speed.
All about wheels and tires271
Wheels and tires
Z

The TIN is a unique identification number. The
TIN enables tire manufacturers to inform pur-
chasers of recalls and other safety-relevant mat-
ters. It makes it possible for the purchaser to
easily identify the affected tires.
The TIN is made up of manufacturer identifica-
tion code;, tire size =, tire type code ?and
manufacturing date A.
DOT (Department of Transportation): Tire
symbol :indicates that the tire complies with
the requirements of the U.S. Department of
Transportation.
Manufacturer identification code: manufac-
turer identification code ;provides details on
the tire manufacturer. New tires have a code
with two symbols. Retreaded tires have a code
with four symbols.
For further information about retreaded tires,
see (
Ypage 279).
Tire size: identifier=describes the tire size.
Tire type code: Tire type code?can be used
by the manufacturer as a code to describe spe-
cific characteristics of the tire.
Date of manufacture: date of manufactureA
provides information about the age of a tire. The
first and second positions represent the week of
manufacture, starting with "01" for the first cal-
endar week. Positions three and four represent
the year of manufacture. For example, a tire that
is marked "3214" was manufactured in week 32
in 2014.
iTire data is vehicle-specific and may deviate
from the data in the example.
Tire characteristics
This information describes the type of tire cord
and the number of layers in sidewall :and
under tire tread ;.
iTire data is vehicle-specific and may deviate
from the data in the example.
Definition of terms for tires and loading
Tire ply composition and material used
Describes the number of layers or the number of
rubber-coated belts in the tread and the sidewall
of the tire. These are made of steel, nylon, pol-
yester and other materials.
Bar
Metric unit for tire pressure. 14.5038 pounds
per square inch (psi) and 100 kilopascals (kPa)
are the equivalent of 1 bar.
DOT (Department of Transportation)
DOT-marked tires fulfill the requirements of the
U S Department of Transportation.
Normal occupant weight
The number of occupants for which the vehicle
is designed multiplied by 68 kilograms (150 lbs).
Uniform Tire Quality Grading Standards
A uniform standard to grade the quality of tires
with regards to tread quality, tire traction and
temperature characteristics. The quality grad-
ing assessment is made by the manufacturer
following specifications from the U.S. govern-
ment. The ratings are molded into the sidewall of the tire.
All about wheels and tires273
Wheels and tires
Z

PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire width
in percent.
Tire pressure
This is pressure inside the tire applying an out-
ward force to each square inch of the tire's sur-
face. The tire pressure is specified in pounds per
square inch (psi), in kilopascals (kPa) or in bar.
The tire pressure should only be corrected when
the tires are cold.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and
Rif the vehicle has not been driven further than
1 mile (1.6 km)
Tread
The part of the tire that comes into contact with
the road.
Bead
The tire bead ensures that the tire sits securely
on the wheel. There are several steel wires in the
bead to prevent the tire from coming loose fromthe wheel rim.
Sidewall
The part of the tire between the tread and the
bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
parts and more than 2.3 kg (5 lbs). These
optional extras, such as high-performance
brakes, level control, a roof rack or a high-per-
formance battery, are not included in the curb
weight and the weight of the accessories.
TIN (Tire Identification Number)
This is a unique identifier which can be used by
a tire manufacturer to identify tires, for example
for a product recall, and thus identify the pur-
chasers. The TIN is made up of the manufactur-
er's identity code, tire size, tire type code and
the manufacturing date.
Load bearing index
The load bearing index (also load index) is a code
that contains the maximum load bearing capa-
city of a tire.
Traction
Traction is the result of friction between the tires
and the road surface.
TWR (Tongue Weight Rating)
The TWR specifies the maximum permissible
weight that the ball coupling of the trailer tow
hitch can support.
Treadwear indicators
Narrow bars (tread wear bars) that are distrib-
uted over the tire tread. If the tire tread is level
with the bars, the wear limit of áin (1.6 mm)
has been reached.
Occupant distribution
The distribution of occupants in a vehicle at their
designated seating positions.
Total load limit
Nominal load and luggage load plus 68 kg
(150 lbs) multiplied by the number of seats in
the vehicle.
Changing a wheel
Flat tire
You can find information on what to do in the
event of a flat tire in the "Breakdown assistance"
section (
Ypage 246).
Rotating the wheels
GWARNING
Interchanging the front and rear wheels may
severely impair the driving characteristics if
the wheels or tires have different dimensions. The wheel brakes or suspension components
may also be damaged. There is a risk of acci-
dent.
Rotate front and rear wheels only if the wheels and tires are of the same dimensions.
Changing a wheel275
Wheels and tires
Z

!On vehicles equipped with a tire pressure
monitor, electronic components are located
in the wheel.
Tire-mounting tools should not be used near
the valve. This could damage the electronic
components.
Only have tires changed at a qualified spe-
cialist workshop.
Always observe the instructions and safety
notes under "Installing a wheel" (
Ypage 276).
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.
On vehicles that have the same size front and
rear wheels, you can rotate the wheels accord-
ing to the intervals in the tire manufacturer's
warranty book in your vehicle documents. If no
warranty book is available, the tires should be
rotated every 3,000 to 6,000 miles (5,000 to
10,000 km). Depending on tire wear, this may
be required earlier. 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 rota-
ted. Check the tire pressure and reactivate the
tire pressure monitor if necessary (
Ypage 265).
Direction of rotation
Tires with a specified direction of rotation have
additional benefits, e.g. if there is a risk of hydro-
planing. You will only gain these benefits if the
correct direction of rotation is observed.
An arrow on the sidewall of the tire indicates its
correct direction of rotation.
You may mount the spare wheel against the
direction of rotation. Adhere to the time restric-
tion on use as well as the speed limitation speci-
fied on the spare wheel.
Storing wheels
Store tires that are not being used in a cool, dry
and preferably dark place. Protect the tires from
oil, grease, gasoline and diesel.
Mounting a wheel
Preparing the vehicle
GWARNING
When you remove the spare wheel from the
spare wheel bracket, the vehicle’s weight dis-
tribution changes. If the vehicle is already
raised, the jack could tip over. There is a risk
of injury.
Remove the spare wheel from the spare wheel
bracket before lifting the vehicle.
XStop the vehicle on solid, non-slippery and
level ground.
XApply the parking brake.
XBring the front wheels into the straight-ahead
position.
XShift the automatic transmission to position
j.
XSwitch off the engine.
XRemove the vehicle tools and jack from the
vehicle (Ypage 244).
XRemove the spare wheel from the spare wheel bracket (Ypage 245).
XSafeguard the vehicle against rolling away.
Securing the vehicle to prevent it from
rolling away
XPlace chocks or other suitable items under
the front and rear of the wheel that is diago-
nally opposite the wheel you wish to change.
Raising the vehicle
GWARNING
If you do not position the jack correctly at the
appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
!Only position the jack at the appropriate
jacking point of the vehicle. Otherwise, you
could damage the vehicle.
276Changing a wheel
Wheels and tires