re: <ALL>Re: Sport vs. HD Bilstein

[albert jenab <jenab@xxxxxxx>]

Are you guys sure this is correct regarding "recent" HD vs. Sports?
Shorter springs are generally (a lot) stiffer springs.  I would want more
aggressive "valving" to go with them.  I can't believe the Bilstein
engineers would be so stupid as to recommend the same damping for widely
varying spring rates.  Oh, and there is no C shock listed for a E36 BMW
(for example) in their catalog, so only one damping rate per car?  Doesn't
make sense.  

Example: there's a 45% difference in spring rates between the stock springs
and the ubiquitous Eibach Pro-Kit springs I recently put on a Miata, lowers
the car about 1.25" all around.  Turns out Bilstein doesn't make a Sport
for it and believe me, with the HD's it's way underdamped.  I am having a
set of the HD's revalved to Sport specs for it.

BTW, "valving" on Bilsteins are really thin shim stacks with various
thicknesses and preloads, one set on either side of the piston.  The fluid
goes through an uncovered hole in the opposite side of the piston and then
bends these shims to create the damping force.  Thus the "deflected disk"
terminology.  So there really aren't any "valves", there are just these
shims covering up holes in the piston.  So the difference between a HD and
Sport "valving" is just a slightly different set of shims.  Everything else
internally is the same.  This is true for their monotubes, at least.
- -Al
95 M3

- ------------------------------
Date: Wed, 2 Dec 1998 08:48:39 -0600 (CST)
From: Jefrem Iwaniw <jiwaniw@domain.elided>
Subject: <ALL>Re: Sport vs. HD Bilstien

Just to clarify this statement -- it is true only for "recent" models.
There actually was a difference in valving in older models (e.g. 2002
shocks) between HD and sport.

- - ------------------------------------
- - -Jefrem Iwaniw, jiwaniw@domain.elided, '72 2002, '94 525i


On Wed, 2 Dec 1998 GGray657@domain.elided wrote:

> The only difference between the SPORT and HD shocks are the overall shock
> length. The HD shocks are for use with stock non lowered springs. The SPORT
> shock is around one to one and a half inches shorter to work with lowering
> springs. The internal valving is identical. The comfort shock has a less
> aggressive valving, both compression, and rebound. So say's the Bilstien
tech
> guy. 
> 
> GGray 
> 

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