Chevrolet 2004 Astro Owner's Manual page 273

(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.
(B) Tire Performance Criteria Specification (TPC
Spec): 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) Dual Tire Maximum Load: Maximum load that can
be carried and the maximum pressure needed to
support that load when used in a dual configuration. For
information on recommended tire pressure see
Inflation - Tire Pressure on page 5-66 and Loading Your
Vehicle on page 4-30 .
LT-Metric Tire
5-59