Gene,
What happens when you lower any new Dakota without changing the spindle is
you get excessive bump steer when the vehicle rolls
in a corner. This is caused by the steering geometry. The factory
compromised when they placed the steering rack and it sits too low
in the chassis, hence when the vehicle is lowered excessively, the tie rods
are at a severe angle to the rack. If you look at the location of
the factory outer tie rod, you will notice that it is really close to the
bottom of the rim, which doesn't allow you to play with the vertical height
of the ball joint (that is if you stay with 15" rims). If you don't 'slam'
the truck, you can actually get the tie rods to sit really close to level.
This is why I am working on a 2 inch drop only. This problem is most
noticeable when you lower the vehicle without increasing the rate of the
sway bar and/or the spring rate. My factory springs are 600 #/in, which I
always felt they were way to soft, the truck never really felt balanced
(i.e. the front tended to bounce, not the kind of bouncing from worn out
shocks). What a higher spring rate does is keep the suspension from
compressing too far over bumps, only allowing a slight bit more overall
compression than the softer springs. Installing larger sway bars will also
help with bump steer during roll. When the outside suspension compresses in
a corner, larger sway bars will keep the to corners of the suspension at the
same relative height to the body, so the wheels don't try to point in
different directions, giving the twitchy handling that everyone speaks of.
When I run with lowered stock rate springs and bars, I can feel the steering
wheel shake when I hit uneven bumps. The problem is reduced significantly
with the higher rates. I won't lie to you, it doesn't eliminate the
problem, but it keeps it down to controllable levels.
I currently am running a 725 #/in front spring with 1 7/16" sway bar in the
front. Also, the jounce bumpers HAVE to be removed and shorter ones
installed, otherwise you will be constantly riding on them. (We are
including these in our front spring kits). Since Dodge designed funny end
links that use a ball joint, we are mounting to the stock links. You may
shorten and weld the stock links to level the bar. On the rear we've
designed it to ride at the stock rate, until you load it, then we've got a
new overload leaf. I also recommend changing the rear jounce bumper to a
slightly shorter one as well (We are still playing around with different
configurations for these). The rear sway bar that I have on there now is a
7/8" (~10% higher than stock). This setup is pretty good, the truck stays
very level in corners with only a slight bit of understeer. I go canyon
running often and have a blast. I'm still fine tuning the sway bar setup to
get the balance right. I also care about the ride of the truck, and the
increased spring rate doesn't feel uncomfortable, like some sports cars,
harder yes, teeth rattling no. The only problem that I have is that, when
unloaded, my regular cab shortbed rearend feels a bit rough on some roads,
but then if I softened it up too far, I wouldn't be able to haul anything at
all (the GMC Syclone comes to mind). Extended cab models and long beds
don't have this problem. We've developed suspension kits for several
different truck lines and all of them have this problem, there's just no
weight on the rear of regular cab short bed models to help with the ride.
Unfortunately, I find my truck a lot more stable a higher speeds, so I'm
increasing my chances of getting a speeding ticket.
I have read about the two inch dropped a-arms. These will lower the
vehicle, but they WON'T change the geometry of the suspension, the tie rod
joints for the steering have not changed with respect to the ball joints, so
the bump steer problems will still be there, especially if you stay with the
soft stock spring rates. All these arms do is lower the spring perch inside
the arm, lowering the truck.
I hope this info helps you. I'm an engineer, not a professional writer, so
if any of this confuses you, let me know and I will clarify.
Later
Gary Pinkley
gapinkley@earthlink.net
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