Tire Designations - Buick Regal Owner's Manual

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 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 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 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
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.
(D) Construction Code
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
the wheel in inches.
(F) Service Description
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
A two digit
:
A
:
Diameter of
:
These
: