Tire Terminology And Definitions - Cadillac STS 2011 Owner's Manual

(B) Tire Width The three digit number indicates
:
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio A two digit number that
:
indicates the tire height to width measurements.
For example, if the tire size aspect ratio is 60, as
shown in item C of the illustration, it would mean
that the tire's sidewall is 60 percent as high as it
is wide.
(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) Service Description
represent the load index and speed rating of the
tire. The load index represents the load carrying
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load.
A letter code is used to
:
These characters
:

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
:
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.
This means the combined
6-55