GMC 2012 Savana Owner's Manual page 303

For example, if the tire size
aspect ratio is 75, as shown
in item C of the light truck
(LT Metric) tire illustration, it
would mean that the tire's
sidewall is 75 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.
Load Range.
service description indicates the
load index and speed rating of a
tire. If two numbers are given as
in the example, 120/116, then
this represents the load index for
single versus dual wheel usage
(single/dual). The speed rating
is the maximum speed a tire is
certified to carry a load. This
does not apply to Goodyear
LT225/75R16 G949 RSA
and Goodyear LT225/75R16
A
G933 RSD commercial truck
tires; see the dual tire and
single tire maximum load and
load range letter designations on
the tire sidewall.
of air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
The
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.
of a tire's height to its width.
cords that is located between
the plies and the tread. Cords
may be made from steel or other
reinforcing materials.
The amount
steel wires wrapped by steel
cords that hold the tire onto
the rim.
in which the plies are laid at
alternate angles less than
90 degrees to the centerline of
the tread.
The
The relationship
A rubber coated layer of
The tire bead contains
A pneumatic tire