Tire Designations; Tire Terminology And Definitions - Buick Encore 2022 Owner's Manual

194 Vehicle Care
(6) Tire Size A combination of letters
:
and numbers define a tire's width,
height, aspect ratio, construction type,
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 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).
Accessory Weight
weight of optional accessories. Some
examples of optional accessories are
automatic transmission, power
windows, power seats, and air
conditioning.
Aspect Ratio
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.
These
:
The amount of air inside
:
The combined
:
The relationship of a
: