That does it!  Can't you guys (Larry and Steve) see that what Larry says
below totally supports the non-preload contingent of the list (which is
almost everyone except larry and steve).  By tightening the knurled
spring adjuster up a little (see Larry's caveat of _with nobody on the
bike_ ie. suspension is topped out and the spring is constrained) you
effectively insert a spacer.  Then when you sit on the bike, loading it,
the sag is less and the rider rides a bit higher.  There are two very
different conditions being mixed up here:  loaded with sag and
unloaded/topped out.
The preload is increased ON THE BIKE when unlaoded and topped out and
you tighten the adjuster.  Once you load the system (van or bike) you
are changing the ride height.
Preload is only effected when you have a constrained spring in the case
of the UNLOADED and TOPPED out suspension.

> Motorbike tension adjusters are similar in their effect.
> With nobody sitting on the bike, the spring might be extended all the
> way, limit of travel. (On a vanagon that almost never happens)
> Now you tighten the adjuster and you compress the spring, but not
> raising the height of the bike, but just increasing the tension on the
> spring. (with nobody on the bike)
> Once you get back on, the bike will of course sag less, since the
> springs are now more stiff. ?????

the spring is NOT more stiff, you've just raised the position of the
lower perch.

> Does this mean a vanagon is like a motorbike with someone big
> sitting on it ????  imho

if you put someone big on your bike it would sag more for the same
spring adjuster setting.

so the westy isn't leaning, that was fixed that by increasing the ride
height of that side by raising it with a spacer at one end of the spring
not by making the spring any stiffer.  I wouldn't go sticking any
spacers inbetween the coils as that will limit your useable travel.
Spacers inbetween the coils will make the spring stiffer and if you use
Larry's method of thinking about unreasonable extremes then with spacers
inbetween each coil it will no longer be acting like a spring, but like
a solid rod REALLY stiff--no suspension at all.  You guys could do
that--just remove all the suspension components and put screw jacks in
there and load level all day long :)

later,
fred