GMC 2012 Sierra Series Owner's Manual page 458

10-58 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 tire illustration, it
would mean that the tire's
sidewall is 75 percent as high as
it is wide.
(D) Construction Code
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) Service Description
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.
A
:
Light Truck (LT Metric) Tire
(A) Light Truck (LT Metric)
Tire The United States version
:
of a metric tire sizing system.
The letters LT as the first two
characters in the tire size mean
a light truck tire engineered to
standards set by the U.S. Tire
and Rim Association.
These
:
I n f o r ma t i o n P r o v i d e d b y :
(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
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.
A
: