Posted for "Mark R Steitle" <mark.steitle@austin.utexas.edu>:

 Rick,
 Nose gear shimmy has been a well documented problem with the Lancair ES. You
can check the archives on the ES list for more details that you care to know.
 The good news is that Lancair has come up with a strut mod that adds a second
o-ring.  Do you know if your strut has been upgraded?  If not, I recommend
that you send your strut back to Lancair for the strut upgrade.  And don't
continue to fly until it is corrected.  If it has had the upgrade, my guess is
a damaged o-ring.  You can check the damping by using two oiled steel plates.
  
 Good luck,
 Mark Steitle