GMC 2007 Yukon XL Owner's Manual page 486

(E) 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.
(F) Tire Ply Material: The type of cord and
number of plies in the sidewall and under the tread.
(G) Single Tire Maximum Load: 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 490 and Loading Your Vehicle on page 390.
486
Tire Size
The following examples show the different parts of
a tire size.
Passenger (P-Metric) Tire
Light Truck (LT-Metric) Tire
(A) Passenger (P-Metric) Tire: The 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.