Maintenance
40
7
G201004AUN
4. Tire ply composition and material
The number of layers or plies of rub-
ber-coated fabric are in the tire. Tire
manufacturers also must indicate the
materials in the tire, which include
steel, nylon, polyester, and others.
The letter "R" means radial ply con-
struction; the letter "D" means diago-
nal or bias ply construction; and the
letter "B" means belted-bias ply con-
struction.
G201005AUN
5. Maximum permissible inflation
pressure
This number is the greatest amount
of air pressure that should be put in
the tire. Do not exceed the maximum
permissible inflation pressure. Refer
to the Tire and Loading Information
label for recommended inflation
pressure.
G201006AUN
6. Maximum load rating
This number indicates the maximum
load in kilograms and pounds that
can be carried by the tire. When
replacing the tires on the vehicle,
always use a tire that has the same
load rating as the factory installed
tire.
G201007BUN
7. Uniform tire quality grading
Quality grades can be found where
applicable on the tire sidewall
between tread shoulder and maxi-
mum section width.
For example:
TREADWEAR 200
TRACTION AA
TEMPERATURE A
Tread wear
The tread wear grade is a compara-
tive rating based on the wear rate of
the tire when tested under controlled
conditions on a specified govern-
ment test course. For example, a tire
graded 150 would wear one-and-a-
half times (1½) as well on the gov-
ernment course as a tire graded 100.
The relative performance of tires
depends upon the actual conditions
of their use, however, and may
depart significantly from the norm
because of variations in driving
habits, service practices and differ-
ences in road characteristics and cli-
mate.
These grades are molded on the
side-walls of passenger vehicle tires.
The tires available as standard or
optional equipment on your vehicles
may vary with respect to grade.WARNING - Tire age
Tires degrade over time, even
when they are not being used.
Regardless of the remaining
tread, it is recommended that
tires generally be replaced after
six (6) years of normal service.
Heat caused by not climates or
frequent high loading condi-
tions can accelerate the aging
process. Failure to follow this
Warning can result in sudden
tire failure, which could lead to
a loss of control and an acci-
dent involving serious injury or
death.
741
Maintenance
Traction - AA, A, B & C
The traction grades, from highest to
lowest, are AA, A, B and C. Those
grades represent the tires ability to
stop on wet pavement as measured
under controlled conditions on spec-
ified government test surfaces of
asphalt and concrete. A tire marked
C may have poor traction perform-
ance.
Temperature -A, B & C
The temperature grades are A (the
highest), B and C representing the
tire’s resistance to the generation of
heat and its ability to dissipate heat
when tested under controlled condi-
tions on a specified indoor laboratory
test wheel.
Sustained high temperature can
cause the material of the tire to
degenerate and reduce tire life, and
excessive temperature can lead to
sudden tire failure. Grades B and A
represent higher levels of perform-
ance on the laboratory test wheel
than the minimum required by the law.
G201100AEN
Tire terminology and definitions
Air Pressure: The amount of air
inside the tire pressing outward on
the tire. Air pressure is expressed in
pounds per square inch (psi) or kilo-
pascal (kPa).
Accessory Weight : This means the
combined weight of optional acces-
sories. Some examples of optional
accessories are, automatic transaxle
power seats, and air conditioning.
Aspect Ratio : The relationship of a
tire's height to its width.
Belt: A rubber coated layer of cords
that is located between the plies and
the tread. Cords may be made from
steel or other reinforcing materials.
Bead : The tire bead contains steel
wires wrapped by steel cords that
hold the tire onto the rim.
Bias Ply Tire : A pneumatic tire in
which the plies are laid at alternate
angles less than 90 degrees to the
centerline of the tread.
WARNING
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests,
and does not include accelera-
tion, cornering, hydroplaning,
or peak traction characteristics.
WARNING - Tire temperature
The temperature grade for this
tire is established for a tire that
is properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
build-up and possible sudden
tire failure. This can cause loss
of vehicle control and serious
injury or death.
