10-46 Vehicle Care
(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 Identificat ion Number
(TIN)
: The letters and numbers
following the 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.
(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 10‑61.
(G) Maximum Cold Inflation
Load Limit
: Maximum load that
can be carried and the
maximum pressure needed to
support that load.
Tire Designations
Tire Size
The following is an example of a
typical passenge r vehicle
tire size.
(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.
(B) Tire Width
: The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.