I am inquiring about rear parallel leaf springs & shackle length. My question is how many leaves should you use in a rear spring & how long should the rear schackels be, we are trying to lower the rear of a car about 2 inches it is fiberglass & is light, 4 leafs per side. The shackles point up from the frame to the spring eyes & are 4 1/2 inches long center to center on the bolts. It also has air bags & no air in them at the time. So my question is could I get away with removing 1 or 2 leaves then lengthen the shackles some to lower it then replumb the rear bags to run off of the pump system versis just fill with an air hose. It also rides a little on the stiff side now in the rear. The car has air bags in the front with seperate shocks. Overall effect is to lower the rear about 2 to 2 1/2 inches & soften the ride. Any good sugestions.
I think the shackle length is pretty close to what most stock leaf spring vehicles run. I'd probably pull the second shortest leaf out and see how it does. With the bags you can compensate for passenger and extra weight with the bags to maintain the ride height you want. Cadillac has done that for over 40 years with their airshock leveling system.
You could probably drop the shackle length to 3", but whatever you drop the shackle by, you'll get half that in static height drop. So the 1.5" less will only get you .75" drop. I wouldn't go any less than 3" or you'll get spring binding.
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