Frank Ball's Pre-'97 Dakota Rear Anti-Sway Bar FAQ
Dodge puts a good anti-sway bar on the front of most
Dakotas (it depends
on what options you get), but there is no rear
anti-sway bar available
from Dodge.
There are three manufacturers for
front and rear anti-sway bars for the
Dakota: Hellwig (SportTech), Addco,
and Suspension Techniques.
The stiffness of the anti-sway bar depends on
two things: the diameter
of
the bar (bigger is stiffer) and the length of
the arms going from the
pivot points to the axle (shorter is stiffer). I
don't have data for
the
length of the arms on the different sway bars, but
I think they are
close
enought that the difference in diameters dominates
in determining the
overall stiffness.
The stiffness of the bar is
proportional to the diameter of the bar
raised
to the 4th power, so a small
increase in diameter yields a large
increase
in stiffness. The Hellwig bar
is 3/4", the Addco bar is 7/8", and the
Suspension Techniques bar is
15/16". If we use the Hellwig bar as a
starting point we can calculate
that the Addco bar is 85% stiffer and
the
Suspension Techniques bar is 144%
stiffer (32% stiffer than the Addco
bar).
How stiff is good? Is more
better? Anti-sway bars do several things.
They reduce body roll in turns.
This is good, so more is better if this
is all we consider. The ratio of
the stiffness of the front bar to the
stiffness of the rear bar will have a
huge effect on understeer or
oversteer. As the stiffness of the rear sway
bar is increased
understeer
will decrease, eventually leading to oversteer.
So don't go sticking a
massive rear anti-sway bar on a Dakota with no
front anti-sway bar (or a
small diameter front anti-sway bar), the result
could be dangerous
handling (Oversteer is tricky, if you don't correct for
it you spin out.
Understeer is safer, you just run wide in a turn and you
can easily turn
in tighter to compensate. Almost all new vehicles are
designed to
understeer).
The last effect of anti-sway bars concerns only
offroad driving. They
reduce the ability of the suspension to track over
very rough terrain,
which can cause the truck to get stuck because a drive
wheel gets
airborn.
Imagine terrain where the left front and right rear
suspension is
compressed. The opposite two wheels will need to extend
fully to reach
the ground. The anti-sway bars resist this kind of twisting
force and
can
keep a wheel from reaching the ground. Serious 4WD owners
often have
sway
bar disconnects or just don't use them at all.
On my '95
SLT club cab the front bar is 1 3/32" diameter. Stock the
handling
understeered very hard. With the Addco rear anti-sway bar
added
it still
understeers, but not near as much (and it will oversteer under
certain
conditions like bumpy turns or hard acceleration).
Most Dakota front
anti-sway bars are 1 1/8" and come with rubber
bushings.
Urethane bushing
kits are available. Urethane is stiffer and lasts
longer,
but
squeaks.
The Shelby Dakotas came with both front and rear anti-sway bars,
but
they
are both rather small in diameter.
Here are some testimonials
from the mailing list:
From: DFuller288@aol.com
Date: Thu, 4 Jan 1996 21:06:24 -0500
Subject: Dakota Anti-Sway Bar
Just installed a Hellwig
SportTech rear anti sway bar on 93' 4x4 club
cab
with 5.2L. Unit fit
perfectly out of box. Simple bolt on operation
took
less than 1 hour. Bar
makes a noticeable difference in reduced roll in
hard
cornering. Got unit
from Summit Racing Equip. for about $100 including
shipping. Well worth
the money for in handling
improvement.
I installed a Addco rear anti-sway bar shortly after buying
my truck.
It
is 7/8" diameter. It goes across the frame in front of the
spare, with
a
dogleg to clear the spare tire, and the arms attach to the
lower shock
mounts. It required drilling four 1/2" holes in the frame.
Polyurethane
bushings. About $180. Body roll is greatly reduced, and so
is
understeer. Highly recommended. The truck still understeers on
a
smooth
road, but it is tolerable. Of course the back end will bounce out
when
it
hits a bump. I'm wondering if better rear shocks would help, but
I'm
know
that the solid rear axle suspension has its limitations. There is
no
loss
of ground clearance with the Addco bar. I think that the Hellwig
bar
mounts under the rear axle with the arms going back to attach to
the
frame
(the opposite of the Addco bar), and so the Hellwig bar might
reduce
ground clearance under the rear axle.
Frank Ball
frankb@sr.hp.com (707) 794-4168 work
Rohnert Park CA '95 Dakota SLT Club Cab V8 5-Speed 2WD
Date: Mon, 8 Jan 1996 21:21:42 -0500
From: MagnumMrk@aol.com
Subject: Re: rear sway bars
Hey!
I did some calling today and found Suspension
Techniques has a 1 1/8"
front
and a 15/16" rear sway bar kit for sale.The
cheapest place I found to
buy it
is A.S.A.P.The 2 bars come complete with
urethane bushings for
$229.00.If you
don't already have a front sway bar
they will sell you an installation
kit.
Mark
Corrections and additions are welcome.
Frank Ball 1UR-M frankb@sr.hp.com (707) 794-4168 work
Hewlett Packard (707) 794-3038 fax (707) 538-3693 home
1212 Valley House Drive Kawi KDX200, Yamaha XT350 YZF600R Seca 750
Rohnert Park CA 94928-4999 '95 Dakota SLT Club Cab V8 5-Speed 2WD
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