Pontiac 2004 GTO - Manual (Page 243)

(A) Tire Size: The tire size is a combination of letters
and numbers used to define a particular tire’s width,
height, aspect ratio, construction type and service
description. See the “Tire Size” illustration later in this
section for more detail.
(B) Department of Transportation (DOT): The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.
(C) Tire Identification Number (TIN): The letters and
numbers following DOT code are the Tire Identification
Number (TIN). The TIN shows the manufacturer
and plant code, tire size, and date the tire was
manufactured. The TIN is molded onto both sides of the
tire, although only one side may have the date of
manufacture.
(D) Tire Ply Material: The type of cord and number of
plies in the sidewall and under the tread.
(E) Uniform Tire Quality Grading (UTQG): Tire
manufacturers are required to grade tires based on three
performance factors: treadwear, traction and
temperature resistance. For more information see
Uniform Tire Quality Grading on page 5-66.
(F) Maximum Cold Inflation Load Limit: Maximum
load that can be carried and the maximum pressure
needed to support that load. For information on
recommended tire pressure see Inflation - Tire Pressure
on page 5-58 and Loading Your Vehicle on page 4-30.
5-53