These leaf spring pads are used when installing a new rear end housing or when relocating your leaf springs to accommodate a larger rear tire. The steel adjustable leaf spring pads clamp to any 3" axle tube. Simply locate and center the axle housing, set the pinion angle and leaf spring positions, and then clamp the spring pads in place. We recommend you permanently weld the spring pads in place after you set the pinion angle. The spring pads are compatible with 2-1/2" wide leaf springs.