Posted for "Christopher Zavatson" <Christopher.Zavatson@udlp.com>:

Bob,
I wouldn't get too hung up on the 100# value as a cut-off.  My
experience has shown that the 100# number has lots of head room built
in, provided the rest of the nose gear system is assembled and working
properly.  As has been discussed here before, too much preload in the
pivot bearings or binding in the linkage anywhere throughout its travel
is something to be avoided.  It can make even a 100# + strut
insufficient.
I perform all my emergency gear extension tests at 100 KIAS.  In an
actual emergency I would of course slow down to something like 80, but
this higher speed tells me much more about the entire system than just
measuring the strut force.  Only once in 5 years have I replaced the
strut due to low pressure.  This was after it failed the extension test
at 100KIAS.  Slowing down just a few knots allowed the gear to fully
extend on its own.  At this point the strut was in the neighborhood of
75#.  More pressure is a good thing, to a point, but in this case there exist
other variables that are of greater significance than a few psi
variation in strut pressure.   80,100, or 120psi should all work.  If it
doesn't there are problems elsewhere that needs to be addressed.  The
one thing we should not do is crank up the strut pressure to mask other
potential issues.  If your system is clean, the 100 plus or minus a few
will work just fine.  When you get a chance, find out at what speed  the
nose gear fails to extend.  I believe that to be a better test of the
system.
Chris Zavatson
N91CZ
L360std