5668-1. Specifications
Light truck (LT) tire
A tire designated by its manufacturer as pri-
marily intended for use on lightweight trucks
or multipurpose passenger vehicles
Load ratingThe maximum load that a tire is rated to carry
for a given inflation pressure
Maximum load ratingThe load rating for a tire at the maximum per-
missible inflation pressure for that tire
Maximum permissible
inflation pressureThe maximum cold inflation pressure to which
a tire may be inflated
Measuring rimThe rim on which a tire is fitted for physical
dimension requirements
Open spliceAny parting at any junction of tread, sidewall,
or innerliner that extends to cord material
Outer diameterThe overall diameter of an inflated new tire
Overall width
The linear distance between the exteriors of
the sidewalls of an inflated tire, including ele-
vations due to labeling, decorations, or protec-
tive bands or ribs
Passenger car tire
A tire intended for use on passenger cars,
multipurpose passenger vehicles, and trucks,
that have a gross vehicle weight rating
(GVWR) of 10,000 lb. or less.
PlyA layer of rubber-coated parallel cords
Ply separationA 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
Tire related termMeaning
5678-1. Specifications
8
Vehicle specifications
*: Table 1 Occupant loading and distribution for vehicle normal load for
various designated seating capacities
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
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 m
The rim on which a tire is fitted for testing, and
may be any rim listed as appropriate for use
with that tire
TreadThat portion of a tire that comes into contact
with the road
Tread ribA tread section running circumferentially
around a tire
Tread separationPulling 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 fixtureThe fixture used to hold the wheel and tire
assembly securely during testing
Tire related termMeaning
