Tire Terminology And Definitions - Saturn 2009 OUTLOOK Owner's Manual

5-42 Service and Appearance Care
Tire Size
The following illustration shows
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
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 carry capacity a tire is
certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.
A two-digit Tire Terminology and
:
Definitions
Air Pressure
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).
A letter
:
Accessory Weight
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.
Diameter of
:
Aspect Ratio
of a tire's height to its width.
These
:
Belt
cords that is located between the
plies and the tread. Cords may
be made from steel or other
reinforcing materials.
The amount of
:
This means
:
The relationship
:
A rubber coated layer of
: