GMC Sierra 2023 Manual page 120

Passenger (P-Metric) Tire
(1) Passenger (P-Metric) Tire
United States 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.
(2) Tire Width The 3-digit number
:
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio A 2-digit number that
:
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in
item (3) of the illustration, it would
mean that the tire's sidewall is
75 percent as high as it is wide.
(4) Construction Code
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.
(5) Rim Diameter
The wheel in inches.
:
(6) 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.
Light Truck (LT-Metric) Tire
(1) Light Truck (LT-Metric) Tire
United States version of a metric tire
sizing system. The letters LT as the first
two characters in the tire size mean a
A letter code is
:
Diameter of the
:
These
:
The
:
Vehicle Care
light truck tire engineered to standards
set by the U.S. Tire and Rim
Association.
(2) Tire Width The 3-digit number
:
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio A 2-digit number that
:
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in
item (3) 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.
(4) 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.
(5) Rim Diameter Diameter of the
:
wheel in inches.
(6) Load Range Load Range.
:
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