Tire Designations; Tire Terminology And Definitions - Chevrolet 2011 Volt Owner's Manual

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
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; 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
A two digit 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
:
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
combined weight of optional
accessories. Some examples
of optional accessories are,
Diameter of
:
automatic electric drive unit,
power steering, power brakes,
power windows, power seats,
These
:
and air conditioning.
Aspect Ratio
of a tire's height to its width.
Vehicle Care 10-45
The amount
:
The
:
The relationship
: