TIRE SAFETY INFORMATION
3.4 GLOSSARY OF TIRE TERMINOLOGY
RADIAL PLY TIRE A pneumatic tire in which the ply cords that extend to the beads are laid at substantially
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90 degrees to the centerline of the tread.
RECOMMENDED INFLATION PRESSURE-
REINFORCED TIRE
than the corresponding standard tire.
RIM A metal support for a tire or a tire and tube assembly upon which the tire beads are seated.
RIM DIAMETER This means the nominal diameter of the bead seat.
RIM SIZE DESIGNATION This means the rim diameter and width.
RIM TYPE DESIGNATION This means the industry of manufacturer’s designation for a rim by style
or code.
RIM WIDTH
SECTION WIDTH
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.
SPECIAL TRAILER (ST) TIRE The “ST” is an indication the tire is for trailer use only.
TEST RIM
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.
TREAD WEAR INDICATORS (TWI) The projections within the principal grooves designed to give a
visual indication of the degrees of wear of the tread.
VEHICLE CAPACITY WEIGHT
the vehicle’s designated seating capacity.
VEHICLE MAXIMUM LOAD ON THE TIRE The load on an individual tire that is determined 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 determined by distributing
to each axle its share of the curb weight, accessory weight, and normal occupant weight (distrib-
WEATHER SIDE
WHEEL CENTER MEMBER In the case of a non-pneumatic tire assembly incorporating a wheel, a
mechanical device which attaches, either integrally or separably, to the non-pneumatic rim and
provides the connection between the non-pneumatic rim and the vehicle; or, in the case of a
non-pneumatic tire assembly not incorporating a wheel, a mechanical device which attaches,
either integrally or separably, to the non-pneumatic tire and provides the connection between
tire and the vehicle.
WHEEL-HOLDING FIXTURE
testing.