ROC offer a comprehensive range of standard and heavy-duty leaf springs - both parabolic and multi-leaf designs - commonly used in the suspension systems of 4WD vehicles, light commercial vehicles, and some passenger cars. Leaf springs, one of the oldest forms of suspension system predating coil springs, have remained prevalent in light commercial and 4WD vehicles since the mid-20th century due to their ability to evenly distribute loads across the chassis. There are two primary types of leaf springs: the multi-leaf and the parabolic leaf spring. Multi-leaf springs feature a trapezoidal design with stacked, differently-sized leaves. As they deflect, friction between the leaves creates load variations during compression and decompression. The longest leaf has two eyes for attaching to the vehicle body, with the strength of these eyes being critical for safety. U-bolts secure the spring's center to the vehicle axle. In contrast, parabolic springs are designed for low internal friction and minimum weight, possessing fewer leaves with a parabolic shape that minimizes bending stress. The leaves mainly contact at the center and ends, reducing friction. Rubber pads can further alleviate friction. The strength and safety of the eyes are critical in both types. The manufacturing process involves leaf preparation, bending, heat treatment, shot peening, assembling, presetting, and surface treatment, ensuring strength and corrosion protection. Manufacturing plants comply with quality assurance and environmental standards. Safety Please carefully check the 'Build' and 'Notes' relevant to your vehicle within the catalogue when choosing your part. Other designs may exist that are not covered within our range. For safety and OE handling characteristics, we recommend that leaf springs are always replaced in axle pairs. Changing a spring can be a dangerous job and we therefore recommend a recognised repair manual is followed for replacement. When removing a leaf spring, first unfasten the spring from the axle and then from the fitting points on the body of the vehicle. Check and clean all fitting points and repair or replace them as necessary. Always replace U-bolts (spring clamps). When replacing a leaf spring, first fasten the spring to the fitting points on the body of the vehicle and then to the axle. It is important to ensure that U-bolts (spring clamps) are properly tightened to the correct level of torque. A recognised repair manual should be followed to check the correct torque. There should be no movement of the spring between the U-bolts. Any leaf spring breakage between the U-bolts will be due to insufficient tightening (allowing movement) and will not be covered by our warranty. ROC leaf springs are made to the highest standard from top-quality steel in an ISO9001 environment. All springs are inspected and tested before delivery. All ROC leaf springs are produced and finished to OEM standards.