Derek:

you are too kind for words.  My understanding may (or may not) be
sophisticated, but it is wrong.  Pre-loading changes something, but apparently
not the spring rate.  There is no question, though, that my suspension is
firmer with donuts than it was without, but only in the initial travel of
suspension.  So, if spring rate did not change, what did?  The effect is more
than just raising the van.

Fred sent me a flow chart charting the differences spring rate and rebound,
but I am still confused.   I think Jim davis may have hit on something, too,
in p-mail to me....and that is that the spacer compresses the initial softer
spring travel in the progressive rate rear springs, and hence this has the
effect of changing the spring rate in the initial travel.

Anyway, sorry for the groping and misuse of termonology.  But keeping the
objective is sight, the issue is what do the spacers do that firms up the
suspension if they do not change spring rate?
steve

Derek Drew wrote:

> There might be a problem with some of the substance of this post. That is,
> is may be a faulty assumption that the spring is more compressed merely by
> putting shims over it. Putting shims/doughnuts over it raises the vehicle,
> but does not compress the spring more than the spring would be compressed
> without those doughnuts.
>
> The only way to make the spring more compressed would be to increase the
> weight of the van. As Steven's understanding (and writing style!) is
> generally sophisticated, I think we need this whole thing reposted, but
> eliminating the concept that the doughnuts alter the spring rate. I don't
> know why in the case of motorcycles shims under the spring change the
> spring rate, but likely this effect does not apply to Syncro.
>
> At 12:48 AM 6/18/98 -0700, you wrote: