Tire Designations - GMC 2012 Terrain Owner's Manual

(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.
Vehicle Care
(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.
10-49
A two digit
:
A
:
Diameter of
: