The long travel spring under kit was designed for maximum rear suspension performance without making the installation difficult for average person. For best results this kit should be combined with the Dirt King bedcage and Deaver H70HD leaf under springs. The complete package paired with a custom drive shaft allows for 18" of usable travel. The factory drive shaft can be retained but will limit 2" of down travel. Even with the 2" travel loss it still achieves a respectable 16" of wheel travel.