Tire Designations; Tire Terminology And Definitions - GMC 2011 Terrain Owner's Manual

10-48 Vehicle Care

Tire Designations

Tire Size
The following is an example
of a typical passenger vehicle
tire size.
(A) Passenger (P Metric) Tire
The 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.
(B) Tire Width The three digit
:
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
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
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; and the
letter B means belted bias ply
construction.
(E) Rim Diameter
the wheel in inches.
(F) Service Description
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
A two digit 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
of air inside the tire pressing
A
:
outward on each square inch
of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight
combined weight of optional
accessories. Some examples
of optional accessories are
automatic transmission, power
Diameter of
:
steering, power brakes, power
windows, power seats, and air
conditioning.
These
:
Aspect Ratio
of a tire's height to its width.
The amount
:
The
:
The relationship
: