GMC 2010 Savana 1500 Cargo Owner's Manual page 321

Light Truck (LT-Metric) Tire
(A) Light Truck (LT-Metric) Tire
States version of a metric tire sizing system. The
letters LT as the first two characters in the tire
size means a light truck 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 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.
The United
:
(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) Load Range Load Range.
:
(G) 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.
A letter code is used to
:
The service description
:
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