GMC 2012 Savana - Manual (Page 320)

Black plate (54,1) GMC Savana Owner Manual - 2012 - 2nd - 11/11/11
10-54 Vehicle Care
(B) Tire Width : The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio : A two‐digit
number that indicates the tire
height‐to‐width measurements.
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.
(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 : Diameter of
the wheel in inches.
(F) Load Range : Load Range.
(G) Service Description : The
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 G933
RSD commercial truck tires; see
the dual tire and single tire
maximum load and load range
letter designations on the tire
sidewall.
Tire Terminology and
Definitions
Air Pressure : The amount 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 : 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.
Aspect Ratio : The relationship
of a tire's height to its width.
Belt : A rubber coated layer of
cords that is located between
the plies and the tread. Cords
may be made from steel or other
reinforcing materials.