Chevrolet 2007 TrailBlazer Owner's Manua page 451

(E) Tire Ply Material: The type of cord and number
of plies in the sidewall and under the tread.
(F) 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 469.
(G) 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 457
and Loading Your Vehicle on page 356.
Light Truck (LT-Metric) Tire
(A) Tire Size: The tire size code 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.
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