Gary
Who do you work for????
Colin
Gary Pinkley wrote:
> 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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