Promaster SuperSprings Steel Helper Spring

SuperSprings rear steel helper springs for Promaster vans and cab chassis, 1500, 2500, and 3500.  SuperSprings are a simple, bolt-on, steel helper spring that can improve rear-end sag and help stabilize sway & body roll. Great for heavy RV's, contractor vans, and towing.   The patented roller system on the spring ends allow for good flex. As the factory springs flatten under load the helper spring ends are able to slide or roll to their new location rather than dragging or causing friction. This helps eliminate binding that causes poor flex and limits travel of the suspension, which can result in a hard or harsh ride. That is why many traditional add a leafs, helper springs or assist springs have a bad reputation for creating a brick hard ride. The roller system also allows tension between the factory springs and the Supersprings, this keeps the product from rattling. Smooth, quiet, and strong. All steel helpers springs will firm an unloaded vehicle to some extent. For loaded vehic