Flat, curved metal leaves stacked on top of each other in several layers that are installed below the axle. Trailers are normally built with either leaf spring axles or torsion axles. Leaf spring axles are the most widely used suspension system due to its affordability. Leaf springs provide a spring like damping action.
Unlike torsion axles, leaf spring axles are bolted to the leaf spring. The leaf spring is attached at both ends to the trailer.