Steven,

I've annotated your message - hopefully to add clarity.

Steven X. Schwenk wrote:
>
> You're right...I am going beyond where I need to to make my point, though, which
> is that inserting a donut above the spring does not raise the van per se, it just
> increases spring tension and thus reduces suspension sag.

NOT true - with the addition of the 'donut', the weight of the vehicle has not
increased, therefore the compressive force on the spring(s) is unchanged,
therefore the spring deflection due to the compressive force is unchanged ==>>
The van rides higher by the thickness of the donut.

  I suspect that to only
> increase height without also increasing spring tension, you would have to lift
> the vehicle at the point where it attaches to the suspension.

The point of load bearing from the chassis to the wheels is the spring(s) -
instead of tension, this is actually a compressive load on the spring(s)

..I have not thought
> this part through, the comment about extending the shock mounts is the beginning
> of a guess on how to do that and was made prematurely.
> steve
>

Since the chassis rides higher with donuts installed, depending on the
thickness of the donuts and also the age-related spring deformation (metallic
creep results from loading over time) "sag", one may or may not need to
install longer shocks to compensate for the added height. One should measure
to determine the necessity of changing shocks. It is fairly critical that the
suspension stops limit travel - not the shocks!

Best Regards,

Ken Stich
Former Mechanic
BS Mechanical Engineer
MS Aerospace Engineer
80 Vanagon-L
57 Vintage Oval Bug