Saturn 2008 Astra - Manual (Page 232)

(D) Maximum Cold Inflation
Load Limit
: Maximum load that
can be carried and the maximum
pressure needed to support
that load.
(E) Tire Inflation : The
temporary use tire or compact
spare tire should be inflated
to 60 psi (420 kPa). For more
information on tire pressure
and inflation see Inflation - Tire
Pressure on page 9-46.
(F) Tire Size : A combination of
letters and numbers define a
tire’s width, height, aspect ratio,
construction type, and service
description. The letter T as
the first character in the tire size
means the tire is for temporary
use only.
(G) 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.
Tire Size
The following illustration shows
an example of a typical
passenger 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.
(C) Aspect Ratio : A two-digit
number that indicates the tire
height-to-width measurements.
For example, if the tire size
aspect ratio is 60, as shown in
item C of the illustration, it would
mean that the tire’s sidewall is
60 percent as high as it is wide.
9-42 Vehicle Service and Care