What is a shackle & why would you want to extend it?
A shackle is a very important part your suspension, connecting the leaf spring and the vehicle frame. It enables the leaf spring to operate through length changes as your suspension performs. The leaf packs, or leaf springs, are placed centrally under the axle of your vehicle.
Shackles also support your vehicle's weight, given they are the primary part of the suspension. As a leaf spring flexes, its distance from the main eye to shackle eye fluctuates. When you upgrade your suspension or use a lift kit, they will probably be supplied new shackles.
