Leaf springs are typically the most important part of a truck or SUV suspension. They are the backbone of your vehicles support, providing load capacity and impacting your ride quality. A broken leaf spring can cause your vehicle to lean or sag, and is strongly recommended to purchase replacement leaf springs. You can also add a leaf to existing springs to increase load capacity. Also available are heavy duty or hd leaf springs for heavy use or commercial applications to increase towing or hauling capacity.