madizell said:
You must have some brands in mind and without the names, it is hard to comment. Can't say I have ever seen a 6" lift "kit" or "system" (at this point a distinction without a difference) sold by a major brand name in this country that gave no thought to steering geometry in their designs. Quite the contrary. Seems to me that all of them have accommodated these many build parameters at least well enough to place the final result withing a range of adjustability that allows for reasonable steering alignments when installed as intended.
My point was only that a spring spacer intended to install over stock components might have been determined not to push adjustments outside stock parameters, but the same spacer on top of an after market assembly may well do just that, i.e., make alignment impossible or at the least, problematic. Or it might not, but who knows if it has not been determined. Neither the maker of the spacer nor the maker of the lift kit are going to recommend you mix their products on your truck unless they already know they will successfully mix.
I put spring spacers in the same category with lift blocks for leaf springs. Not the best option going, and certainly not "plenty good". Spacers pre-droop upper and lower arms, placing them below the median of their designed range of travel. You then have to adjust all the adjustable parts to compensate or your steering will be off. You probably also should change out your shocks. I acknowledge that this can be done. I just don't feel it is a "good" thing to do.
Whether it is a spacer or a new coil, any type of lift pre-droops the CAs, even with the use of adjustable, stock location arms. Until you start dealing with control arm drop brackets (available for the XJ and ZJ) or Long arms, the stock geometry, using stock locations is never the same once a vehicle is lifted.
Blocks are bad in my book because of the extra leverage they create with the new Moments and such, but I think that as with all things, spacers are perfectly acceptable. After all, companies like OME market "trim packers" as part of their suspension systems.
On to the death wobble comments...
Death Wobble is NOT a light shimmy. Death wobble is when you hit a small bump or pothole, and your suspension goes in to some crazy harmonic vibration, shaking your entire vehicle to pieces until you slow down and pull over to the side of the interstate in the middle of Phoenix Rush hour traffic...
I had DW on my old XJ, and it was due to wallowed out UCA bushings on the axle side. I replaced these and the problem was gone.
I would surmise that the dual stabilizers do mask some inherent design issue when the steering angles increase with the lift...just a guess though.