Date:         Wed, 1 Jul 1998 22:30:12 -0700
Reply-To:     Nathaniel Merrill <nmerrill@PARAMETRIX.COM>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Nathaniel Merrill <nmerrill@PARAMETRIX.COM>
Subject:      Spacers and springs again! (steve is right and here is why)
Comments: To: Vanagon@VANAGON.COM
Content-Type: text/plain; charset=US-ASCII

If you follow what I am about to say then I think you will see that the preload contingent (IE stiffer springs) is correct.  Bare with me...
Three points:
1)  The resistance a spring gives to further compression increases as it is compressed.  It is harder to compress a spring more after it has already been compressed some.  We know this to be true because it requires more force (weight) to continue to compress a spring as you go.  Agreed?
2) What do you do to put in a spacer? You must compress the spring in the suspension in order to fit in a spacer.   Why? because the shock limits the travel of the lower A-arm when you jack up the car and thus the limits the space between the spring perches.  So we must compress the spring to fit in the spacer. (it is preloaded)   That must mean that the spring is now forced into a shorter space and thereby artificially compressed.  It is in fact exerting more force on the shock...pushing the control arms apart with more force than before.  Agreed?
3) So now we lower the van's weight onto the spring which is already compressed some.  What happens?  Remember that the spring is already exerting more force trying to spread the control arms apart because it is compressed some by the spacer. So the vans weight, being the same as it was before, encounters a spring which is pushing on its boundaries (perches) harder then before (no spacer).  That means that the weight of the van is counterbalanced by more resistance to compression (see #1) then the un-compressed (no spacer) spring.  
This must mean that the vans weight does not compress the spring the same amount as it did before,  which means that the van sits higher (the suspension sags less).  BUT
It also means that the spring is now in a further compressed state.  Why?  because 1.  we had to compress it to get the spacer in and 2. the vans weight is now compressing it further.  That means that in order to compress the spring any more (like when the suspension tries to absorb a bump) it requires more force be applied to it than it would have if it was not already compressed some.  So when a bump comes along on the road and the tire rolls over it, it must compress a spring which is already compressed more than it is with out the spacer.  So what happens?  The force of the bump  does not compress the spring as far as it would have had the spring not been compressed to a greater extent already (no spacer). So the suspension travels less (because the spring compresses less) and thus the suspension   FEELS STIFFER! 
If you think any of this is incorrect then say exactly why.  What we are all here for is to learn about the things we love. Saying WRONG or otherwise does not move us along the path to enlightenment!
Bye 
Nat 
Sunny Seattle 
1991 Syncro Westy