you also have to be careful with shackles in the front because the basicly rotate the axle assembly. causing your steering knuckles not to be strait up and down. thios causes problems with your steering componanats wearing out and bad tire wear and freaky steering at highway speeds. all not good. when you see the hord core wheelers with the big long shackles for added articulation they have also lowered the solid spring mount at the other end of the leaf spring so your dropping both sides of it keeping every thing within spec.