Link calculator link http://mysite.verizon.net/triaged/4linkcalcv15html/index.htm
l It seems to work but you need to download Adobe SVG to get the graphics which you don't really need. Here is another that explains everything for you so you have a beter understanding of what it is that the first link is telling you to do. http://www.therangerstation.com/Magazine/winter2007/4_link_tech.htm
I should also add the coilover link which helps determine what size, where to place and how coilovers or coils\shocks work. http://www.pirate4x4.com/tech/billavista/coilovers/Part_1/
this is part 1 of a two part article it has a spring rate calculator and tons of good info along with breakdowns of actual fox coilovers.