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).
Load-bearing index: load-bearing indexAis a
numerical code that specifies 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 356).
Example:
Load-bearing index 91 indicates a maximum
load of 1,356 lb (615 kg) that the tires can bear.
For further information on the maximum tire
load in kilograms and lbs, see (
Ypage 363).
For further information on the load bearing
index, see "Load index" (
Ypage 363).
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.
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 indexAand 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. 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-weather tires and winter tires
IndexSpeed rating
Q M+S2up to 100 mph (160 km/h)
T M+S2up to 118 mph (190 km/h)
H M+S2up to 130 mph (210 km/h)
V M+S2up to 149 mph (240 km/h)
iNot all tires with the M+S marking provide
the driving characteristics of winter tires. In
addition to the M+S marking, winter tires also
have the isnowflake symbol on the tire
wall. Tires with this marking fulfill the require-
ments of the Rubber Manufacturers Associa-
tion (RMA) and the Rubber Association of
Canada (RAC) regarding the tire traction on
snow. They have been especially developed
for driving on snow.
2Or M+S ifor winter tires.
362All about wheels and tires
Wheels and tires
An electronic speed limiter prevents your vehi-
cle from exceeding the following speeds:
RAll vehicles (except Mercedes-AMG GLS 63):
130 mph (210 km/h)
RMercedes-AMG GLS 63: 155 mph (250 km/h)
RMercedes-AMG GLS 63 with increased top
speed: 174 mph (280 km/h)
The speed rating of tires mounted at the factory
may be higher than the maximum speed that the
electronic speed limiter permits.
Make sure that your tires have the required
speed rating, e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "Tires" section (
Ypage 371).
Further information about reading tire data can
be obtained from any qualified specialist work-
shop.
Load index
In addition to the load bearing index, load
index :may be imprinted after the letters that
identify speed index Bon the sidewall of the
tire (
Ypage 361).
RIf no specification is given: no text (as in the
example above), represents a standard load
(SL) tire
RXL or Extra Load: represents a reinforced tire
RLight Load: represents a light load tire
RC, D, E: represents a load range that depends
on the maximum load that the tire can carry at
a certain pressure
iTire data is vehicle-specific and may deviate
from the data in the example.
Maximum load rating
Maximum tire load :is the maximum permis-
sible weight for which the tire is approved.
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 356).
iThe actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
DOT, Tire Identification Number (TIN)
US tire regulations stipulate that every tire man-
ufacturer or retreader must imprint a TIN in or on
the sidewall of each tire produced.
The TIN is a unique identification number. The
TIN enables the tire manufacturers or retreaders
to inform purchasers of recalls and other safety-
relevant matters. 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 :marks that the tire complies with the
All about wheels and tires363
Wheels and tires
Z
Speed rating
The speed rating is part of the tire identification.It specifies the speed range for which the tire is
approved.
GTW (Gross Trailer Weight)
The GTW is the weight of a trailer including the
weight of the load, luggage, accessories etc. on
the trailer.
GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight of
the vehicle including fuel, tools, the spare wheel,
accessories installed, occupants, luggage and
the drawbar noseweight, if applicable. The gross
vehicle weight must not exceed the gross vehi-
cle weight rating GVWR as specified on the vehi- cle identification plate on the B-pillar on the
driver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permissible gross
weight of a fully loaded vehicle (the weight of the
vehicle including all accessories, occupants,
fuel, luggage and the drawbar noseweight, if
applicable). The gross vehicle weight rating is
specified on the vehicle identification plate on
the B-pillar on the driver's side.
Maximum loaded vehicle weight
The maximum weight is the sum of:
Rthe curb weight of the vehicle
Rthe weight of the accessories
Rthe load limit
Rthe weight of the factory installed optional
equipment
Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure is
bar. 100 kilopascals (kPa) are the equivalent of
1 bar.
Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall of
the tire. This specifies the load-bearing capacity
more precisely.
Curb weight
The weight of a vehicle with standard equipment
including the maximum capacity of fuel, oil and
coolant. It also includes the air-conditioning sys- tem and optional equipment if these are instal-
led in the vehicle, but does not include passen-
gers or luggage.
Maximum load rating
The maximum tire load is the maximum permis-
sible weight in kilograms or lbs for which a tire is approved.
Maximum permissible tire pressure
Maximum permissible tire pressure for one tire.
Maximum load on one tire
Maximum load on one tire. This is calculated by
dividing the maximum axle load of one axle by
two.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire widt h
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 kilopascal (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 from
the wheel rim.
All about wheels and tires365
Wheels and tires
Z
Notes on the vehicle equipment – always equip
the vehicle:
Rwith tires of the same size on a given axle (left
and right)
Rwith the same type of tires at a given time
(summer tires, winter tires, MOExtended
tires)
Vehicles equipped with MOExtended tires are
not equipped with a TIREFIT kit at the factory. It
is therefore recommended that you additionally
equip your vehicle with a TIREFIT kit if you mount
tires that do not feature run-flat properties, e.g.
winter tires. A TIREFIT kit may be obtained from
a qualified specialist workshop.
Emergency spare wheel
Important safety notes
GWARNING
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:
Radapt your driving style accordingly and
drive carefully.
Rnever mount more than one spare wheel or
emergency spare wheel that differs in size.
Ronly use a spare wheel or emergency spare
wheel of a different size briefly.
Rdo not switch ESP®off.
Rhave 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.
!Mercedes-AMG vehicles with
"Minispare" emergency spare wheel: only
use the "Minispare" emergency spare wheel
on the rear axle. If you mount the
"Minispare" emergency spare wheel on the
front axle, this could result in damage to the
brake system. If a tire on the front axle is defective, an intact
wheel from the rear axle must first be
replaced with the "Minispare" emergency
spare wheel. The damaged wheel on the front
axle can then be replaced by the undamaged
wheel from the rear axle.
Make sure to note the placard on the
"Minispare" emergency spare wheel.
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 emer-
gency spare wheels.
General notes
You can ask for information regarding permitted emergency spare wheels at an authorized
Mercedes-Benz Center.
Mounting the emergency spare wheel is descri-
bed under "Mounting a wheel" (
Ypage 367).
You should regularly check the pressure of the
emergency spare wheel, particularly prior to
long trips, and correct the pressure as neces-
sary (
Ypage 349). The value on the wheel is
valid.
An emergency spare wheel may also be moun-
ted 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.
When you are driving with the collapsible spare
wheel mounted, the tire pressure loss warning
system or the tire pressure monitor cannot func-
tion reliably. Only restart the tire pressure loss
warning system or tire pressure monitor when
the defective wheel has been replaced with a
new wheel.
Vehicles with tire pressure monitor: after
mounting an emergency spare wheel, the sys-
tem may still display the tire pressure of the
removed wheel for a few minutes. The value dis-
played for the mounted emergency spare wheel
is not the same as the current tire pressure of
the emergency spare wheel.
372Emergency spare wheel
Wheels and tires