Re: Caster shims?

[Howard R Pletcher <n9ads@xxxxxxxx>]

Caster is the distance that the tire contact patch trails the point that
an almost-vertical line through the ball joints would contact the ground
(although caster is normally measured in degrees by the angle the line
through the ball joints makes with the vertical) .  Putting the wide part
of the wedge at the rear in a spring-under rotates the theoretical point
where this line contacts the ground toward the rear of the vehicle,
probably putting it behind the actual contact point of the tire which is
negative caster, while putting the wide part at the front increases
caster.  

Driving with negative caster would be much like trying to push a grocery
cart while trying to keep its casters pointed in the wrong direction. 

As Joel says, the effect is reversed for a spring-over.

Mark your calendars, Joel was correct on 7/6/03!      :-)

Howard


On Sun, 6 Jul 2003 16:36:05 -0700 (PDT) joel brodsky
<travelall1974@domain.elided> writes:
> I think this formula only applies to SOA.  Most Scout
> IIs are sprung under and to improve caster and make
> the handling better, the thicker part of the wedge
> should indeed be in the front.  This way it will make
> the caster angle 'lie-back' which is what smooths out
> the ride, like a motorcycle.