Tire Terminology And Definitions - Pontiac 2008 Vibe Owner's Manual

Tire Size
The following illustration shows an example of a
typical passenger car tire size.
(A) Passenger (P-Metric) Tire
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.
(B) Tire Width he three-digit number indicates
: T
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 70, as
shown in item C of the illustration, it would mean
that the tire's sidewall is 70% as high as it is wide.
5-52
The United States
:
(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 range and the speed rating
of a tire. The load range represents the load carry
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load. 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.
A letter code is used to
:
These characters
: