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6-1. Specifications
Ply separationA parting of rubber compound between adjacent 
plies
Pneumatic tire
A mechanical device made of rubber, chemicals, fab-
ric and steel or other mate rials, that, when mounted 
on an automotive wheel, provides 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 corresponding 
standard tire
Section width
The linear distance between the exteriors of the side-
walls of an inflated tire, excluding elevations due to 
labeling, decoration, or protective bands
SidewallThat portion of a tire between the tread and bead
Sidewall separationThe 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 mThe rim on which a tire is fitted for testing, and may be 
any rim listed as appropriate for use with that tire
Tr e a dThat portion of a tire that comes into contact with the 
road
Tire related termMeaning