Tire Size - Pontiac G3 2009 Owner's Manual

(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 5-57.
(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.

Tire Size

The following illustration shows an example of a
typical passenger car tire size.
(A) Passenger (P-Metric) Tire
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.
The United States
:
(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 70, as
shown in item C of the illustration, it would mean
that the tire's sidewall is 70% as high as it is wide.
(D) Construction Code
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
represent the load index and speed rating of the
tire. The load index represents the load carry
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified
to carry a load.
A letter code is used
:
These characters
:
5-53