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392 OperationTires and wheels
4
This is the maximum permissible tire in-
flation pressure for the tire.
Always follow the recommended tire in-
flation pressure (
\2
page 361) for proper
tire inflation.
iFor illustrative purposes only. The ac-
tual data on tires is specific to each
vehicle and may vary from the data
shown in the above illustration.
Warning
G
Never exceed the maximum tire inflation
pressure. Follow recommended tire infla-
tion pressures.Do not underinflate tires. Underinflated
tires wear excessively and/or unevenly,
adversely affect handling and fuel econo-
my, and are more likely to fail from being
overheated.
Continued
Warning (Continued)
G
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride
comfort, wear unevenly, increase stop-
ping distance, and result in sudden defla-
tion (blowout) because they are more
likely to become punctured or damaged
by road debris, potholes etc.
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Page 395 of 666
393 Operation
Tires and wheels
4
1Plies in side wall
2Plies under tread
This marking tells you about the type of
cord and number of plies in the side wall
and under the tread.
Accessory weightThe combined weight (in excess of those
standard items which may be replaced)
of automatic transmission, power steer-
ing, power brakes, power windows, pow-
er seats, radio, and heater, to the extent
that these items are available as factory-
installed equipment (whether installed
or not).
Tire ply material
iFor illustrative purposes only. The
actual data on tires is specific to
each vehicle and may vary from the
data shown in the above illustration.
Tire and loading terminology
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Page 396 of 666

394 OperationTires and wheels
4
Air pressureThe amount of air inside the tire pressing
outward on each square inch of the tire.
Air pressure is expressed in pounds per
square inch (psi), or kilopascal (kPa) or
bars.Aspect ratioDimensional relationship between the
tire section height and the section width
expressed in percentage.
BarAnother metric unit for air pressure.
There are 14.5038 pounds per square
inch (psi) to 1 bar; there are
100 kilopascals (kPa) to 1 bar.BeadThe tire bead contains steel wires
wrapped by steel cords that hold the tire
onto the rim.Cold tire inflation pressureTire inflation pressure when your vehicle
has been sitting for at least 3 hours or
driven no more than 1 mile (1.6 km).
Curb weightThe weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if
so equipped, air conditioning and addi-
tional optional equipment, but without
passengers and cargo.DOT (D
epartment O
f T
ransportation)
A tire branding symbol which denotes
that the tire meets the requirements of
the U.S. Department of Transportation.
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395 Operation
Tires and wheels
4
GAWR (G
ross A
xle W
eight R
ating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR
for the front and rear axle indicated on
the certification label located below the
driver’s seat on the mounting pillar.
GCWR (G
ross C
ombination W
eight
R
ating) The GCWR is the total permissible
weight of vehicle and trailer when
weighed in combination including a
150 lbs (68 kg) allowance for the pres-
ence of a driver. It is indicated on the
certification label located below the driv-
er’s seat on the mounting pillar.GTW (G
ross T
railer W
eight)
The GTW is the weight of the trailer plus
the weight of all cargo, equipment, lug-
gage etc. loaded on the trailer.
GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare
wheel, installed accessories, passen-
gers and cargo and, if applicable, trailer
tongue load. The GVW must never ex-
ceed the GVWR indicated on the certifi-
cation label located below the driver’s
seat on the mounting pillar.
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396 OperationTires and wheels
4
GVWR (G
ross V
ehicle W
eight R
ating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight
of the vehicle including all options, pas-
sengers, fuel, and cargo and, if applica-
ble, trailer tongue load). It is indicated
on the certification label located below
the driver’s seat on the mounting pillar.Kilopascal (kPa)The metric unit for air pressure. There
are 6.9kPa to 1psi; another metric unit
for air pressure is bars. there are
100 kilopascals (kPa) to 1 bar.
Maximum load ratingThe maximum load in kg and pounds
that can be carried by the tire.Maximum loaded vehicle weightThe sum of curb weight, accessory
weight, vehicle capacity weight and pro-
duction options weight.Maximum tire inflation pressureThis number is the greatest amount of
air pressure that should ever be put in
the tire under normal driving conditions.
Normal occupant weightThe number of occupants the vehicle is
designed to seat, multiplied by 68 kg
(150 lbs).Occupant distributionThe distribution of occupants in a vehi-
cle at their designated seating positions.
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397 Operation
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4
Production options weightThe combined weight of those installed
regular production options weighing
over 5 lbs (2.3 kg) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy
duty battery, and special trim.PSI (P
ounds per S
quare I
nch)
A standard unit of measure for air pres-
sure. Another metric unit for air pres-
sure is bar or kilopascal (kPa).
Recommended tire inflation pressureRecommended tire inflation pressure for
normal driving conditions listed on the
tire and loading information placard
1 or
on the tire inflation pressure placard lo-
cated on the driver’s door B-pillar.
Provides best handling, tread life and
riding comfort.
RimA metal support for a tire or a tire and
tube assembly upon which the tire
beads are seated.
Side wallThe portion of a tire between the tread
and the bead.TIN (T
ire I
dentification N
umber)
Unique identifier which facilitates efforts
by tire manufacturers to notify purchas-
ers in recall situations or other safety
matters concerning tires and gives pur-
chases the means to easily identify such
tires. The TIN is comprised of the “man-
ufacturer’s identification mark”, “tire
size”, “tire type code” and “date of man-
ufacture”.
1. For vehicles with a gross weight capacity less
than 10 000 lbs (4 536 kg) (USA only).
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398 OperationTires and wheels
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Tire load ratingNumerical code associated with the
maximum load a tire can support.Tire ply composition and material
usedThis indicates the number of plies or the
number of layers of rubber-coated fabric
in the tire tread and side wall. Tire man-
ufacturers also must indicate the ply ma-
terials in the tire and side wall, which
include steel, nylon, polyester, and oth-
ers.
Tire speed ratingPart of tire designation; indicates the
speed range for which a tire is approved.TractionForce exerted by the vehicle on the road
via the tires. The amount of grip provid-
ed.TreadThe portion of a tire that comes into con-
tact with the road.
Treadwear IndicatorsNarrow bands, sometimes called
“wear bars” that show across the tread
of a tire when only
1/16
in (1.6 mm) of
tread remains.
TWR (T
ongue W
eight R
ating)
Maximum permissible weight on the
trailer tongue.
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399 Operation
Tires and wheels
4
Uniform tire quality grading stan-
dardsA tire information system that provides
consumers with ratings for a tire’s trac-
tion, temperature and treadwear. Rat-
ings are determined by tire
manufacturers using government test-
ing procedures. The ratings are molded
into the side wall of the tire.
Vehicle capacity weightRated cargo and luggage load plus 68 kg
(150 lbs) times the vehicle’s designated
seating capacity.Vehicle maximum load on the tireLoad on an individual tire that is deter-
mined by distributing to each axle its
share of the maximum loaded vehicle
weight and dividing it by two.
Rotating tiresWarning
G
Rotate front and rear wheels only if they
are of the same dimension.Changing the tire dimension for an axle could cause the tire to come into contact
with the vehicle body or axle parts. Dam-
age to the tire or the vehicle may be the
result.
Continued
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