Maintenance
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7
Traction - AA, A, B & C
The traction grades, from highest to
lowest, are AA, A, B and C. The
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. The grades repre-
sent the tire’s resistance to the gen-
eration of heat and its ability to dissi-
pate heat when tested under con-
trolled conditions on a specified
indoor laboratory test wheel.
Sustained high temperature can
cause the material of the tires to
degenerate and reduce tires life, and
excessive temperature can lead to
sudden tires failure. Grade C corre-
sponds to a level of performance
which all passenger vehicle tires must
meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades A
and B represent higher levels of per-
formance on the laboratory test wheel
than the minimum required by the law.
Tire terminology and defini-
tions
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 transmis-
sion, power seats, and air condition-
ing.
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
- 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.