SECTION II. EQUIPMENT DESCRIPTION AND DATA (Con't)
1-8. EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES (Con't).
k. VALVE STEMS (Con't).
(3) Tube, Cured-in Valve Stems. Cured-in valve stems are similar to cured-on valve stems
except that the rubber base is inverted and vulcanized to the inner surface of the tube. The rubber base
may also be vulcanized directly into the rubber body of the tube.
(4) Tube, Spud-Mounted Valve Stems. Spud-mounted valve stems are constructed in two
parts. They are readily identified by absence of a bridge washer and hex nut. Older versions of Spud-
Mounted valve stems are made airtight at the base through a clamping action between the spud base
and stem base. Newer versions of these valve stems have a cured-in spud, whose outside thread accepts
a valve stem replacement with a preformed packing.
(5) Tube, Clamp-in Valve Stem. Clamp-in valve stems for tubes are no longer used except
on some motorcycle and bicycle applications. These valve stems are airtight at the base through
clamping action of the bridge washer and hex nut. Some of these valves stems are threaded the full
length of the stem to accept a second nut, called a rim nut, that holds the valve stem firmly in place on
the rim. The bridge washer is installed with its ends lengthwise to the tube.