I have a '97 ZRT6. *I live in upstate New York & ride the Tug Hill area. *Our trails have come a long way in the past few years but due to high traffic & narrow trails moguls are part of life here. *Because of this I have to rebuild the rear shock (Fox, no reservoir or external adjustment) every 500-700 miles. http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/confused.gif *I have not re-valved the shock, just standard rebuild. *In 1999 I re-valved the front shocks. 3500 miles later I am still riding on the same rebuild with nearly the same performance. *I am curious to know if the ACT or Ryde FX shocks have to be rebuilt this frequently? * * http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/thumbs-up.gif