Nimble
tire/tube valve extender
The rim depth of our CROSSWIND (29mm) and FLY (28mm) requires an
extension to standard length presta tubular tire valves. This valve extender is 1.10
inches (27mm) long and 1/4 inches in diameter (6.1mm) . It is turned
from one piece from aircraft aluminum alloy.
Black.
We
recommend a three step process to prep your tubular tires when
installing. See Tubular tire
advice. Most riders leave extenders in place while training and
racing to facilitate quick tire inflating. The aero advantages of
removing extenders are minimal (varying by wheel configuration, 0.4 to 1.2
grams drag).
Tufo
valve extender
The Tufo 20mm extender offers a slightly higher cost, but sometimes more
functional extension of the length of the tire stem. This extender
threads into the tire stem at the bottom (male thread) and moves the valve
core from the stem to the top (female thread) 
where
it threads into the extender. This leaves the tire valve available
for the tire pump.
The extender is machined from aircraft aluminum. There is also a
small plastic tool available to install the extender and work with the
valve core. This work can also be done (carefully!) with a pair of
needle nose pliers. Note the two small mid section wrench flats for
tightening the extender into the tire stem. Also see our three step tire
set up process Tubular tire
advice.
Again, most riders leave extenders in place exchanging the minimal aero advantages of
removing extenders for the greater control and ease of quick tire
inflation. Removing this style extender removes the tire valve core
and deflates the tire.