In reply to:
are there any other "safety conscientious" suggestions?
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The lift itself has been well covered, but I'll get into steering correction and general pre-lift prep.
Give the suspension and steering joints a complete inspection. (everything IS 15 years old or so...) This
means the spring bushings, kingpin berings for wear, well bearings, tie rod and drag link ends, steering box,
steering damper, anything that moves, particularly on the front axle.
Poly bushings are better than rubber for springs as they are stiffer and help limit sway. a small amount of flex
may be lost but that is small potatoes compared to the safety improvement.
After the lift, check the castor to be sure you still have 3.5-4 deg. less castor will cause the rig to wander
on the highway.
Steering correction. The Breeze Xover was mentioned, and that kit is what I always recomend as the best
design. Others have Xovers steerings and even high steer's that take the tierod above the springs, but the
other Xovers aren as solid as the Breeze, and the high steers change (reverses) the ackerman angle which
will affect the toe-in during turns. Not good, epesially on the street.
Your available options for steering correction are intended to keep the drag link from hitting the springs, and
in some cases to eliminate bump steer, which is a by-product of lifting the chassis and therfor the steering box
higher than stock.
If you look at a stock drag link it is almost perfectly level with the ground. It is also in line with the roll
center of the front axle and that keeps the effective length of the drag link nearly static as the supension
moves. If you look at a lifted rig, regardless of whether it is a spring lift, SPOA or some combination, the
steering box end of the drag link is well above the axle end. If you look at the arc the drag link makes at
the axle end as the supension flexs, it changes where the steering points the wheels as it goes up and down.
this is bump steer, and can be so bad as to cause lane changes on the highway in extreme cases.
Z-link - This is a modified drag link, usually a cut and welded drag link, some are made one piece, that clears
the springs but does not correct bump steer and can even flex and worsen the steering precision. In the
worst case it can bend or break much easier than a straight drag link.
Drop pitman arm - This is limited to about 3" and is only really suitable for spring lifts by itself. an extreme
lift might want to use a drop pitman in combination with another steering correction to give enough correction.
Idler arm - (calmini is the only one I know of) with this system the tie rod is fliped end for end and a shorter
drag link goes to an idler arm, then a second drag link goes bak under the steering box to the reversed tie rod.
its advantage is that it will eliminate bump steer, and allow a change in steering speeds by changeing
the effective length of the pitman arm at the idler arm. Its drawback is tha it hangs low and may hit rocks
in extreme wheeling.
Xover - it doe a goog job correcting steering for 4-6 inch lifts or so. It also gets the drag link up out of the way.
It leaves the tie rod in the stock location where it is vulnerable to rocks.
The Breeze unit attaches to the brake caliper bolts and replaces the kingpin cap, giving it 6 bolted joints,
as well as using the kingpin boss for additional sheer strength, onloading the kingpin bolts slightly. The
Breez is the only one piece arm (that I am aware of) and has a hardened king pin pressed in and welded.
RRO's is a 2 piece arm, the caliper piece welded to the arm, with a pressed king pin. I don't know if it is
hardened. earlier versions only bolted to the 4 kingpin bolts and required re-drilling and taping the knuckle
bolt holes which weakened them. Reports were made of some failing in use hence the design change.
the Spidertrax unit has a bolted bracket down to the stock steering arm on the knuckle and bolts on top of
the kingpin cap I belive.
Other units bolt only to the caliper. This includes the slightly modified Mercedes arms, which are also used in
highsteer conversions. I think this lacks strength, although I have not heard of one failing at the caliper. I
don't like it as it is certain to flex the caliper which is not doing the brakes any good.
High steer - many make them. or you can go with the Mercedes arms on both sides, shorten the tie rod,
and reuse the stock drag link. All designs so far reverse the ackerman angle of the steering knuckle. As
described above, this insures the Toe-in is only correct when steering straight. the shrper the turn, the
further out of toe you are. This cannot be good.
Wow, I seem to have done a long version on this subject, but that's OK, I'll save it for future use.