Tire Terminology and
De nitions
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).
Accessory Weight
:This means
the combined weight of optional
accessories. Some examples
of optional accessories are,
automatic transmission, power
steering, power brakes, power
windows, 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.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in pounds per square
inch (psi) or kilopascals (kPa)
before a tire has built up heat
from driving. SeeTire Pressure
on page 9-54.
Curb Weight
:The weight of
a motor vehicle with standard
and optional equipment including
the maximum capacity of fuel,
oil, and coolant, but without
passengers and cargo.DOT Markings
:A code
molded into the sidewall of
a tire signifying that the tire
is in compliance with the U.S.
Department of Transportation
(DOT) motor vehicle safety
standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight
Rating. SeeVehicle Load
Limits on page 8-12.
GAWR FRT
:Gross Axle
Weight Rating for the front axle.
SeeVehicle Load Limits on
page 8-12.
GAWR RR
:Gross Axle
Weight Rating for the rear axle.
SeeVehicle Load Limits on
page 8-12.
9-52 Vehicle Care
