I have an '07 Rubicon Unlimited with a 4.5" Rubicon Express lift. I want to go down to 3.5" springs in the rear. I thought it was a simple spring swap, but I was told by someone that I also need to re-align the rear end. Does anyone know if this is really necessary? I would hate to spend money on something that is not needed.
Do you have an adjustable track bar, or do you have RE's frame side dropdown bracket with the stock trackbar? I would think dropping the lift one inch would change the center of the rear axle. Enough to make a difference , I don't know. An adjustable trackbar would correct the offset. Personally, I don't think you need to worry.
if you have an adjustable track bar you can check center after you put the 3.5 springs on measure the distance from the tires to frame on both sides to see if it is centered the measurement can be within 1/2 inch