(D) Construction Code
indicate the type of ply construction in the tire.
The letter R means radial ply construction; the
letter D means diagonal or bias ply construction;
and the letter B means belted bias ply
construction.
(E) Rim Diameter
Diameter of the wheel in
:
inches.
(F) Load Range
Load Range.
:
(G) Service Description
indicates the load index and speed rating of a
tire. If two numbers are given as in the example,
120/116, then this represents the load index for
single versus dual wheel usage (single/dual).
The speed rating is the maximum speed a tire is
certified to carry a load.
Tire Terminology and Definitions
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).
6-54
A letter code is used to
:
The service description
:
Accessory Weight
:
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
:
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. See Inflation - Tire Pressure on
page 6 57.
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.
This means the combined
The amount of air pressure