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333 Operation
Tires and wheels
Tire type code
The code4 (
page 332) may, at the 
option of the manufacturer, be used as a 
descriptive code for identifying significant 
characteristics of the tire.
Date of manufacture
The date of manufacture5 (
page 332) 
identifies the week and year of manufac-
ture. 
The first two figures identify the week, 
starting with “01” to represent the first full 
week of the calendar year. The second two 
figures represent the year.
For example, “3202” represents the 32nd 
week of 2002.
Maximum tire load
1Maximum tire load rating
The maximum tire load is the maximum 
weight the tires are designed to support.For more information on tire load rating 
(
page 328)
For information on calculating total and 
cargo load capacities (
page 317). 
iFor illustration purposes only. Actual 
data on tires is specific to each vehicle 
and may vary from data shown in above 
illustration.
Warning!
G
Do not overload the tires by exceeding the 
specified load limit or vehicle capacity 
weight as indicated on the placard located 
on the driver’s door B-pillar. Overloading the 
tires can overheat them, possibly causing a 
blowout. Overloading the tires can also 
result in handling or steering problems, or 
brake failure. 
     
        
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337 Operation
Tires and wheels
Tire and loading terminology
Accessory weight
The combined weight (in excess of those 
standard items which may be replaced) of 
automatic transmission, power steering, 
power brakes, power windows, power 
seats, radio, and heater, to the extent that 
these items are available as 
factory-installed equipment (whether 
installed or not).
Air pressure
The 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 ratio
Dimensional relationship between tire 
section height and section width 
expressed in percentage.Bar
Another 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.
Bead
The tire bead contains steel wires wrapped 
by steel cords that hold the tire onto the 
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle 
has been sitting for at least three hours or 
driven no more than one mile (1.6 km). 
Curb weight
The 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 additional 
optional equipment, but without passen-
gers and cargo.DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the 
tire meets requirements of the 
U.S. Department of Transportation.
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 on the driver's 
door B-pillar.
GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the 
vehicle including fuel, tools, spare wheel, 
installed accessories, passengers and 
cargo and, if applicable, trailer tongue 
load. The GWV must never exceed the 
GWVR indicated on the certification label 
located on the driver's door B-pillar. 
     
        
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338 OperationTires and wheelsGVWR (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, passen-
gers, fuel, and cargo and, if applicable, 
trailer tongue load). It is indicated on 
certification label located on the driver's 
door B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are 
6.9 kPa to one psi; another metric unit for 
air pressure is bars. There are 
100 kilopascals (kPa) to one bar.
Maximum load rating
The maximum load in kilograms and 
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight, 
vehicle capacity weight and production 
options weight.Maximum tire inflation pressure
This number is the greatest amount of air 
pressure that should ever be put in the tire 
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is 
designed to seat, multiplied by 
68 kilograms (150 lbs).
Occupant distribution
The distribution of occupants in a vehicle 
at their designated seating positions.
Production options weight
The combined weight of those installed 
regular production options weighing over 
5 lbs (2.3 kilograms) 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 pressure 
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
Recommended tire inflation pressure 
listed on placard located on driver's door 
B-pillar for normal driving conditions. 
Provides best handling, tread life and 
riding comfort.
Rim
A metal support for a tire or a tire and tube 
assembly upon which the tire beads are 
seated.
Sidewall
The portion of a tire between the tread and 
the bead. 
     
        
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339 Operation
Tires and wheels
TIN (T
ire I
dentification N
umber)
Unique identifier which facilitates efforts 
by tire manufacturers to notify purchasers 
in recall situations or other safety matters 
concerning tires and gives purchases the 
means to easily identify such tires. The TIN 
is comprised of “Manufacturer's identifica-
tion mark”, “Tire size”, “Tire type code” 
and “Date of manufacture”.
Tire load rating
Numerical code associated with the 
maximum load a tire can support.
Tire ply composition and material used
This indicates the number of plies or the 
number of layers of rubber-coated fabric in 
the tire tread and sidewall. Tire manufac-
turers also must indicate the ply materials 
in the tire and sidewall, which include 
steel, nylon, polyester, and others.Tire speed rating
Part of tire designation; indicates the 
speed range for which a tire is approved.
Traction
Force exerted by the vehicle on the road 
via the tires. The amount of grip provided.
Tread
The portion of a tire that comes into 
contact with the road.
Treadwear indicators
Narrow bands, sometimes called 
“wear bars” that show across the tread of 
a tire when only 
1/6in (1.6 mm) of tread 
remains.Uniform Tire Quality Grading Standards
A tire information system that provides 
consumers with ratings for a tire's traction, 
temperature and treadwear. Ratings are 
determined by tire manufacturers using 
government testing procedures. The 
ratings are molded into the sidewall of the 
tire.
Vehicle capacity weight
Rated cargo and luggage load plus 
68 kilograms (150 lbs) times the vehicle's 
designated seating capacity.
Vehicle maximum load on the tire
Load on an individual tire that is 
determined by distributing to each axle its 
share of the maximum loaded vehicle 
weight and dividing it by two.