8-1. Specifications- Page 386

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8-1. Specifications

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: Table 1 -Occupant loading and distribution for vehicle normal load for various desig-

nated seating capacities

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 
sidewalls of an inflated tire, excluding elevations 
due to labeling, decoration, or protective 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-Cov-
ered Surfaces, and which is marked with an Alpine 

Symbol (

) on at least one sidewall

Test rim

The rim on which a tire is fitted for testing, and may 
be any rim listed as appropriate for use with that tire

Tread

That portion of a tire that comes into contact with 
the road

Tread rib

A tread section running circumferentially around a 
tire

Tread separation

Pulling away of the tread from the tire carcass

Treadwear indicators (TWI)

The projections within the principal grooves 
designed to give a visual indication of the degrees 
of wear of the tread

Wheel-holding fixture

The fixture used to hold the wheel and tire assembly 
securely during testing

Tire related term

Meaning