Tire Designations; Tire Terminology And Definitions - Chevrolet Equinox 2021 Owner's Manual

and service description. The letter T as
the first character in the tire size means
the tire is for temporary use only.
(7) TPC Spec (Tire Performance Criteria
Specification) Original equipment tires
:
designed to GM's specific tire
performance criteria have a TPC
specification code molded onto the
sidewall. GM's TPC specifications meet
or exceed all federal safety guidelines.

Tire Designations

Tire Size
The example shows a typical passenger
vehicle tire size.
Passenger (P-Metric) Tire
(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
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio
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
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
wheel in inches.
(6) Service Description
The
:
characters represent the load index and
speed rating of the tire. The load index
represents the load carrying capacity a
The 3-digit number
:
A 2-digit number that
:
A letter code is
:
Diameter of the
:
These
:
Vehicle Care
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 amount of air inside
:
the tire pressing outward on each
square inch of the tire. Air pressure is
expressed in kPa (kilopascal) or psi
(pounds per square inch).
Accessory Weight The combined
:
weight of optional accessories. Some
examples of optional accessories are
automatic transmission, 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
:
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.
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