4378-1. Specifications
8
Vehicle specifications
Rim diameter (Wheel diame-
ter)Nominal diameter of the bead seat
Rim size designationRim diameter and width
Rim type designationThe industry manufacturer’s designation
for a rim by style or code
Rim widthNominal distance between rim flanges
Vehicle capacity weight (Total
load capacity)The rated cargo and luggage load plus 150
lb. (68 kg) times the vehicle’s designated
seating capacity
Vehicle maximum load on the
tire
The load on an individual tire that is deter-
mined by distributing to each axle its share
of the maximum loaded vehicle weight,
and dividing by two
Vehicle normal load on the tire
The load on an individual tire that is deter-
mined by distributing to each axle its share
of curb weight, accessory weight, and nor-
mal occupant weight (distributed in accor-
dance with Table 1
* below), and dividing by
two
Weather sideThe surface area of the rim not covered by
the inflated tire
Bead
The part of the tire that is made of steel
wires, wrapped or rein forced by ply cords
and that is shaped to fit the rim
Bead separationA breakdown of the bond between compo-
nents in the bead
Bias ply tire
A pneumatic tire in which the ply cords that
extend to the beads are laid at alternate
angles substantially l ess than 90 degrees
to the centerlin e of the tread
Carcass
The tire structure, ex cept tread and side-
wall rubber which, when inflated, bears the
load
ChunkingThe breaking away of pieces of the tread
or sidewall
CordThe strands forming the plies in the tire
Tire related termMeaning
4398-1. Specifications
8
Vehicle specifications
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 splice
Any parting at any junction of tread, side-
wall, or innerliner that extends to cord
material
Outer diameterThe overall diameter of an inflated new tire
Overall width
The linear distance bet ween the exteriors
of the sidewalls of an inflated tire, including
elevations due to labe ling, decorations, or
protective bands or ribs
Passenger car tire
A tire intended for us e 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
adjacent plies
Pneumatic tire
A mechanical device made of rubber,
chemicals, fabric and steel or other materi-
als, that, when mount ed on an automotive
wheel, provides the tr action 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 substan-
tially 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 bet ween the exteriors
of the sidewalls of an inflated tire, exclud-
ing elevations due to labeling, decoration,
or protective bands
SidewallThat portion of a ti re between the tread
and bead
Tire related termMeaning
