Page 513 of 536

Normal occupant weight
The number of occupants the vehicle is
designed to seat, 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. Ratings are
determined by tire manufacturers using U.S.
government testing procedures. The ratings
are molded into the sidewall of the tire.
Recommended tire pressure
The recommended tire pressure applies to
the tires mounted at the factory.
The Tire and Loading Information placard
contains the recommended tire pressures for
cold tires on a fully loaded vehicle and for the
maximum permissible vehicle speed.
The tire pressure table contains the
recommended tire pressures for cold tires
under various operating conditions, i.e.
differing load and speed conditions.
Increased vehicle weight due to
optional equipment
This is the combined weight of all standard
and optional equipment available for the
vehicle, regardless of whether it is actually
installed on the vehicle or not.
Rim
This is the part of the wheel on which the tire
is mounted.
GAWR (Gross Axle Weight Rating)
The GAWR is the maximum permissible axle
weight. The actual load on an axle must never
exceed the gross axle weight rating. The
gross axle weight rating can be found on the
vehicle identification plate on the B-pillar on
the driver's side.
Speed rating
The speed rating is part of the tire
identification. It specifies the speed range for
which the tire is approved.
GVW (Gross Vehicle Weight)
The gross vehicle weight comprises 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 vehicle
weight rating GVWR as specified on the
vehicle 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 the curb
weight of the vehicle, the weight of the
accessories, the total load limit and the
weight of the optional equipment installed at
the factory.
Definition of terms for tires and loading511Wheels and tiresZ
Page 514 of 536

Kilopascal (kPa)
Metric unit for tire pressure. 6.9 kPa is the
equivalent of 1 psi. Another unit for tire
pressure is bar. There are 100 kilopascals
(kPa) to 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 system and optional equipment
if these are installed in the vehicle, but does
not include passengers or luggage.
Maximum load rating
The maximum load rating in kilograms or
pounds is the maximum weight 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
width in percent.
Tire pressure
This is pressure inside the tire applying an
outward force to each square inch of the tire's
surface. 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.
Tire pressure of cold tires
The tires are cold:
R if the vehicle has been parked without
direct sunlight on the tires for at least three
hours and
R if the vehicle has not been driven more 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.
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
part and more than 2.3 kilograms (5 lbs).
512Definition of terms for tires and loadingWheels and tires
Page 515 of 536

These optional extras, such as high-
performance brakes, level control, a roof rack
or a high-performance battery, are not
included in the curb weight and accessory
weight.
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 purchasers. The TIN is made up of the
manufacturer'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
capacity of a tire.
Traction
Traction is the result of friction between the
tires and the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are
distributed over the tire tread. If the tire tread
is level with the bars, the wear limit of 1
/ 16 in
(1.6 mm) has been reached.
Occupant distribution
The distribution of occupants in a vehicle at
their designated seating positions.
Total load limit
Rated cargo and luggage load plus
68 kilograms (150 lbs) times the vehicle's
designated seating capacity.
Changing a wheel
Flat tire
The "Breakdown assistance" section
( Y page 473) contains information and notes
on how to deal with a flat tire. It also provides
instructions on changing a wheel or mounting
the spare wheel/emergency spare wheel.
Interchanging the wheels
GWARNING
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs. rear),
tire rotation is not possible.
GWARNING
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque of
110 lb-ft (150 Nm).
Only use genuine Mercedes-Benz wheel bolts
specified for your vehicle's rims.
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 3000 to 6000 miles
( 5000 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 pressures.
Information on changing a wheel and
mounting the spare wheel ( Y page 473).
Changing a wheel513Wheels and tiresZ