Re: Ride comfort

[n9ads@domain.elided (Howard R Pletcher)]

On Sat, 21 Feb 1998 08:38:31 -0500 (EST) Chris & Ranae Procyk
<procyk19@domain.elided> writes:
>A piece of knowledge gleaned from the water-cooled VW crowd:
>On a short-wheelbase vehicle with a heavy front weight distribution,
>put the softest shocks you can get in the REAR.
>
>The banging/crashing noises come from the front suspension.
>But in a front-heavy vehicle they aren't what bounces you around.
>Think about it, you have a 750lb engine up there, compared
>to just some empty beer cans and Fritos bags in the back.
>That big weight is not going
>to change direction very easily.  In fact, it's resistance to
>movement is what makes all the banging noise.
>
>But the rear is what bounces the riders.  And this is really
>pronounced in SUV's because the rear shocks usually
>are valved for p/up applications (check the numbers).
>If you look up CJ rear shocks, they're the same as
>1/2 ton p/ups!!!  So they're valved to at least be
>reasonable with 1500lbs in the bed.
>
>Maybe if you haul your mother-in-law around a lot
>this makes sense, but when she isn't there it's
>just annoying.
>
>Will doubling the shocks really halve their damping
>effect?  Seems counter-intuitive to me.  That means
>that if you have an infinite number of shocks you get
>no damping.  I know that works for resistors, but
>dampers??  I'll have to dig up my old textbooks.
>It seems to me that you double the orifice size, but
>you also double the amount of fluid that you're trying
>to push through it.  I thought the purpose of dual shocks
>was only to minimize the heating effect of the fluid.
>by having twice as much fluid.
>
>
I have found that you are right to a degree.  Soft shocks, but firm
enough that you don't bottom out with the somewhat limited travel we have
wll soak up the bumps as much as possible.  However, the biggest
discomfort in the Scout ride comes from the kick that you get on the
rebound of the rear suspension, not the actual bump itself and this is
where heavy duty or double shocks help out.  They may let you feel the
bump more, but they keep you from getting pounded with the rebound.  I
have read that "normal" shocks have about twice as much dampening effect
on compression as on rebound, which may be good on passenger cars, but
not good on stiffly sprung 4x4's.  My experience has been that increasing
the size (or number) of the shocks (at least up to a point) will result a
perceived better ride over the original shocks, although part of the
theory  says softer should be better.  If the Edlebrock shocks do offer
improved rebound control as Steve Stegmann said, then they may well be
worth the extra cost because that is what is needed.

Another design criteria for cars I have read about is to design the
suspension rates such that the front will rebound slowly after a dip
while the rear should rebound more rapidly so that the result is the
whole car tends to float upward at once rather than having the front and
rear going in opposite directions as a Scout does because it appears to
have about the same suspension rates front and rear.  It's not the short
wheelbase itself that gives the choppy ride, but the interaction of the
front and rear suspensions.  Of course, to make a Scout "float" properly,
you would probably have to have about 12" of suspension travel in the
front rather than 3".

Think about this when you drive your Scout and your car over the same
streets and see if doesn't begin to make sense.  Also watch how the
off-road race trucks compress their suspensions and rebound slowly to
soak up the jumps.  I don't know how you can use the info, but it is
interesting to study the effects.

Howard Pletcher
Howteron Products Scout Parts

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