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8
Glossary of
Common Terms
(continued)
LOCK RING - The third piece of a three rim assembly which positions and supports the
side ring to the rim base.
MAXIMUM INFLATION - The highest amount of air pressure allowed, measured
at normal ambient temperatures.
mm - Abbreviation for millimeters.
MULTI-PIECE WHEEL - A wheel assembly in which the rim portion of the wheel
consists of two or more separate parts.
OFFSET - See “OUTSET.”
OPEN SIDE - The side of the wheel opposite the disc face.
OSHA - Abbreviation for the U.S. Department of Labor, Occupational Health
and Safety Administration.
OUTER CAP NUT - A cap nut used to secure the outer stud located wheel
in a dualed wheel pair and thread onto the inner cap nut.
OUTSET - The distance from the mounting surface of the wheel to the rim centerline
when the rim centerline is mounted outboard of the hub face. This dimension
is the same as the 1/2 DUAL SPACING dimension.
PILOT PAD - The raised surfaces on a hub used to center a hub piloted wheel.
PSI - Abbreviation for pounds per square inch.
REVERSIBLE - Term applied to a disc wheel which can be reversed on the hub
without changing the position of the tire centerline.
RIM CENTERLINE - A line to the radial axis of the wheel running through the mid point
between the rim flanges.
RIM FLANGE - That portion of the rim which extends above the rim surface
which retains the tire bead.
RIM - That portion of the wheel which supports the tire.
SIDE RING - A removable piece of a multi-piece wheel assembly which provides
lateral support for one tire bead.
SINGLE CAP NUT - A cap nut used to secure single wheels or outer dual wheels.
STUD - A threaded bolt extending from the hub surface to which the wheels
are secured by the cap nuts.
STUD LOCATED, BALL SEAT MOUNTING - A wheel mounting system which uses
the studs and spherical ball seat cap nuts to center and secure the wheel.
TIRE BEAD - That surface of the tire which contacts the angled surface
of the wheel rim.
TORQUE - The amount of force used to tighten cap nuts. Usually stated in foot-pounds
or kilograms and measured with a torque wrench.
WHEEL MOUNTING FACE - That portion of the wheel face which contacts the hub
or brake drum.
wt. - Abbreviation for weight.