GMC 2010 Savana 1500 Cargo Owner's Manual page 320

(F) Tire Ply Material
:
number of plies in the sidewall and under the
tread.
(G) Single Tire Maximum Load
that can be carried and the maximum pressure
needed to support that load when used as a
single. For information on recommended
tire pressure see Inflation - Tire Pressure on
page 6-63 and Loading the Vehicle on page 5-17.
Tire Size
The following examples show the different parts of
a tire size.
Passenger (P-Metric) Tire
(A) Passenger (P-Metric) Tire
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.
6-58
The type of cord and
Maximum load
:
The United States
:
(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 illustration, it would mean
that the tire's sidewall is 75 percent as high as
it is wide.
(D) Construction Code
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) Service Description
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 letter code is used to
:
These characters
: