Tire Terminology And Definitions - Cadillac CT4 2023 Owner's Manual

326 Vehicle Care
(1) Passenger (P-Metric) Tire
United States version of a metric tire
sizing system. The letter "P" as the first
character in the tire size means a
passenger vehicle tire engineered to
standards set by the U.S. Tire and Rim
Association.
(2) Tire Width The 3-digit number
:
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio A 2-digit number that
:
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in
item (3) of the illustration, it would
mean that the tire's sidewall is
75 percent as high as it is wide.
(4) 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.
(5) Rim Diameter Diameter of the
:
wheel in inches.
The (6) Service Description
:
characters 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.

Tire Terminology and Definitions

Air Pressure
the tire pressing outward on each
square inch of the tire. Air pressure is
expressed in kPa (kilopascal) or psi
(pounds per square inch).
Aspect Ratio
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.
These
:
The amount of air inside
:
The relationship of a
:
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 kPa
(kilopascal) or psi (pounds per square
inch) before a tire has built up heat
from driving. See Tire Pressure 0 328.
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.
:
See Vehicle Load Limits 0 197.
GAWR FRT Gross Axle Weight Rating
:
for the front axle. See Vehicle Load
Limits 0 197.