Cadillac 2006 CTS Owner's Manual page 333

(B) TPC Spec (Tire Performance Criteria
Specification): Original equipment tires designed to
GM's specific tire performance criteria have a TPC
specification code molded onto the sidewall. GM's
TPC specifications meet or exceed all federal safety
guidelines.
(C) DOT (Department of Transportation): The
Department of Transportation (DOT) code indicates
that the tire is in compliance with the U.S. Department
of Transportation Motor Vehicle Safety Standards.
(D) Tire Identification Number (TIN): The letters and
numbers following DOT (Department of Transportation)
code is 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.
(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 5-75.
(G) Maximum Cold Inflation Load Limit: Maximum
load that can be carried and the maximum pressure
needed to support that load.
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