Van Compass rear van leaf springs are suspension upgrades designed to improve ride quality, correct rear sag, and increase load-carrying ability on camper vans, cargo vans and conversions. These springs typically install under your factory springs to combat sag and restore proper ride height near or at GVWR, increase spring rate and reduce bottoming out, and are engineered for specific van models and wheel/tire configurations. These leaf springs are sold in multiple variations; Mini spring packs are lighter and easier to install, and are best when you want to supplement existing springs, while Opti-Rate replacements are more comprehensive, replacing factory springs and offering adjustable ride/weight tuning for diverse payloads. The Opti-rate spring is made up of three distinct parts: the main springs in the primary stage, a 3-leaf secondary stage, and the Adjustable Preload Spacers (APS). | Van Compass Opti-Rate Replacement Spring 303601