646 6-1. Specifications
Tire related termMeaning
Ply A layer of rubber-coated parallel cords
Ply separation A parting of rubber compound between adja-
cent plies
Pneumatic tire A mechanical device made of rubber, chemi-
cals, fabric and steel or
other materials, that,
when mounted on an automotive wheel, pro-
vides the traction and contains the gas or fluid
that sustains the load
Radial ply tire A pneumatic tire in which the ply cords that
extend to the beads are laid at substantially 90
degrees to the centerline of the tread
Reinforced tire A tire designed to operate at higher loads and
at higher inflation pressures than the corre-
sponding standard tire
Section width The linear distance between the exteriors of
the sidewalls of an inflated tire, excluding ele-
vations due to labeling, decoration, or protec-
tive bands
Sidewall That portion of a tire between the tread and
bead
Sidewall separation The parting of the rubber compound from the
cord material in the sidewall
Snow tire A tire that attains a traction index equal to or
greater than 110, compared to the ASTM
E-1136 Standard Reference Test Tire, when
using the snow traction test as described in
ASTM F-1805-00, Standard Test Method for
Single Wheel Driving Traction in a Straight Line
on Snow-and Ice-Covered Surfaces, and which
is marked with an Alpine Symbol ( ) on at
least one sidewall
Te s t r i m The rim on which a tire is fitted for testing, and
may be any rim listed as appropriate for use
with that tire
