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Rating. You can find the Gross Axle Weight Rating
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 a tire is approved.
GVW (Gross Vehicle Weight): the Gross Vehicle
Weight includes the weight of the vehicle includ‐
ing fuel, tools, the spare wheel, accessories
installed, occupants, luggage and the trailer
drawbar noseweight if applicable. The Gross Vehi‐
cle Weight must never exceed the Gross Vehicle
Weight Rating (GVWR) specified on the B-pillar on
the driver's side.
GVWR (Gross Vehicle Weight Rating): the
GVWR is the maximum permitted gross weight of
the fully laden vehicle (weight of the vehicle
including all accessories, occupants, fuel, lug‐
gage and the trailer drawbar noseweight if appli‐
cable). The Gross Vehicle Weight Rating is speci‐
fied on the vehicle identification plate on the B-
pillar on the driver's side.
Maximum weight of the laden vehicle: the
maximum weight is the sum of the vehicle's curb
weight, weight of the accessories, maximum load
and the weight of the factory installed optional
equipment.
Kilopascal (kPa): metric unit for tire pressure.
6.9 kPa are the equivalent of 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 side‐
wall of the tire. This specifies the load-bearing
capacity more precisely.
Curb weight: the weight of a vehicle with stand‐
ard equipment including the maximum capacity
of fuel, oil and coolant. It also includes the air-
conditioning system and optional equipment if
these are installed on the vehicle, but does not
include passengers or luggage.
Maximum tire load: the maximum tire load is
the maximum permissible 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 maxi‐
mum axle load for one axle by two.
PSI (pounds per square inch): standard unit of
measurement for tire pressure.
Aspect ratio: relationship between tire height
and tire width in percent.
Tire pressure: pressure inside the tire applying
an outward force to every 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 correc‐
ted when the tires are cold.
Tire pressure on cold tires: the tires are cold
when the vehicle has been parked with the tires
out of direct sunlight for at least three hours and
the vehicle has been driven less than 1 mile
(1.6 km).
Tire contact surface: the part of the tire that
comes into contact with the road.
Tire bead: the purpose of the tire bead is to
ensure that the tire sits securely on the wheel
rim. There are several wire cores in the tire bead
to prevent the tire from changing length on the
wheel rim.
Side wall: the part of the tire between the tread
and the tire bead.
Special equipment weight: the combined
weight of those optional extras that weigh more
than the replaced standard parts and more than
5 lbs (2.3 kg). These optional extras, such as
high-performance brakes, level control system, a
roof luggage rack or a high-performance battery,
are not included in the curb weight and the
weight of the accessories.
TIN (Tire Identification Number): a unique iden‐
tification number 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 identifi‐
cation code, tire size, tire type code and the man‐
ufacturing 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.
Wear indicator: 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.
Distribution of vehicle occupants: distribution
of vehicle occupants over designated seat posi‐
tions in a vehicle.
Wheels and tires 309
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