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

The following is an example
of a typical passenger vehicle

tire size.

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.
The three digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
A two digit
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.
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.
Diameter of
the wheel in inches.
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.
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).
combined weight of optional
accessories. Some examples
of optional accessories are
automatic transmission, power
steering, power brakes, power
windows, power seats, and air
conditioning.
These
of a tire's height to its width.
The amount
The
The relationship