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Black plate (48,1)
Buick Regal Owner Manual - 2012
10-48 Vehicle Care
(E) Tire Inflation: The
temporary use tire or compact
spare tire should be inflated to
420 kPa (60 psi). For more
information on tire pressure and
inflation see Tire Pressure on
page 10�52.
(F) Tire Size
: Acombinationof
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 performa nce
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet or
exceed all federal safety
guidelines.
Tire Designations
Tire Size
The following is 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 passenge r
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
: Atwo�digit
number that indicates the tire
height�to�wid th measurement s.
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.
(D) Construction Code
: A
letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or bias
ply construction; and the letter B
means belted�bias ply
construction.
(E) Rim Diameter
: Diameter of
the wheel in inches.
(F) Service Description
: These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire