dakota anti-sway bars

From: Frank Ball (frankb@cougar.sr.hp.com)
Date: Sun May 18 1997 - 03:27:23 EDT


} From: Jon Steiger <steiger@ait.fredonia.edu>
} Subject: Anti-sway bars?
}
} I notice that Jules has front and rear anti-sway bars for
} $190 (front) and $180 (rear). Looks like they're made by Addco.
} (I don't know anything about 'em... Are they good?) Someone
} posted earlier that they got an anti-sway bar from Summit for
} about $100 bucks. That's almost half as much $$$. What am I
} missing? :)
}
} I seem to recall something about the '96 Dakotas coming with
} an anti-sway bar of some type already. According to the MPI
} catalog, "Your truck should have come with it, but didn't" (speaking
} of the rear anti-sway bar). Perhaps I already have a front one?
} Or should it be upgraded too? (Yeah, yeah, I suppose I should
} just crawl under there and have a look but I've found other things
} to do.) :) I have to change the oil today, so I'll look then.
}
} How hard are these anti-sway bars to install? Bolt-on? Does any
} pressure have to be taken off the frame while they're installed?

No "pressure" has to be taken off the frame. Some require drilling holes,
some don't.

I'm working on a section for the FAQ on anti-sway bars. I suppose now is
a good time to post it for critique (this is a first draft):

Anti-sway bars for pre-'97 Dakotas:

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.

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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

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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

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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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