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Tire terminology and definitions, Tire terminology and definitions -57 – Cadillac 2009 Escalade EXT User Manual

Page 441

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(C) Aspect Ratio

:

A two-digit number that

indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 75,
as shown in item C of the light truck (LT-Metric)
tire illustration, it would mean that the tire’s
sidewall is 75% as high as it is wide.

(D) Construction Code

:

A letter code is used to

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) Service Description

:

The service description

indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
Speed ratings range from A to Z.

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).

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. See Inflation - Tire Pressure
on page 6-60.

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.

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