[ihc] RE: Pete's mods

["Peter Shubin" <pshubin@xxxxxxxxxxxxx>]

My desire for caster is to have just enough to keep the vehicle tracking
straight.  I had an old VW once and like my Scout it was set up stock at 0
degrees.  When I lowered the front a lot and the rear a little the road
steered the little VW more than I did.  I ended up with 8 degree shims to
compensate for the difference in lowered heights and add in some caster.
This gave a heavy steering feel to such a small and light car but it handled
better than any other stock or modified bug I ever drove and was very stable
at high and very high speeds.

The Scout has a similar problem but a different end use.  I see no need and
have no desire for good over 100 mph handling in the Scout.  I just want it
to track straight with little effort from the driver at normal highway
speeds.  When I add new springs and longer shackles I'll be going in the
wrong direction like I did in my VW.  I will need to build in caster to
compensate for the shackles, any potential rear end sag from carrying heavy
loads, and a couple of degrees for good measure.  If I build in 6 degrees
I'll probably only realize 2 which will probably be plenty.  I have not done
the math yet.  If anyone has please share.

I'll look up the thread you mentioned.

Thanks 

Pete

-----Original Message-----
Date: Thu, 8 Apr 2004 08:33:41 -0700
From: "Jim Grammer" <jgrammer@domain.elided>
Subject: [ihc] Pete's mods

Pete, I have a few thoughts:

*	What caster angle for the front end?

There is a *very* interesting thread on the BB 'new' Tech Talk about the
actual effects of caster, written by a Ford chassis engineer. You may have
to dig for it, I think it was from 2003 but maybe 2002. I don't recall
enough to quote verbatim, but much of what we thought we knew about caster
wasn't neccessarily so. He did illustrate why large amounts of positive
caster aren't really a good thing, which tended to reinforce my observations
that about 2deg is plenty. OTOH, you will get folks who argue that 'more is
better' and that you absolutely positively must have 6deg. IIRC, there are
anecdotal reports of 'fine' handling anywhere from 2deg to 8deg. Maybe 4deg
is a decent compromise for you(?).

*	Should I plan on changing shackles with the Triangle springs?  If
yes, how long should I get or make them?

Some will say absolutely, I say wait 'til your springs arrive and decide for
yourself. Measure along the arch of the spring from eye to eye. 'Flatten
out' that measurement and use it with one end at the fixed spring mount to
see where the end of the  shackle will need to be with the spring at max
flattened length. That will show you the shortest shackle length that will
work with your setup. Allow a bit of fudge factor for flex of the spring
bushings.

*	Where should/can I get the Triangle springs?  If someone knows of a
stiffer spring please let me know.

The SII Triangle springs are a proprietary Light Line design, available from
SSS etc.. The actual spring rates are also proprietary AFAIK. At one point
or another I've had actual spring rates on the other aftermarket springs,
and from low to high they rank Skyjacker, Superlift/Trailmaster(very
close)and Rancho. From Triangle owner reports(and Tom M's polling), I
believe the Triangles are comparable to the Superlift/Trailmaster. John G @
SSS may be able to shed some light on this as long as you're not pressing
him for the actual Triangle #'s ;)

Jim