RE:HD or sport?

[Rodney Moore <m6bigdog@xxxxxxxx>]

Paul,
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well, to get to the point, when i had the stock shocks off, i compared them
to the bilsteins, and they were a bit longer than my stock ones, hum...
interesting, so then when i installed both of them on and when i took the
car off the jack stands they raised my car!! should the shocks do that?? i
heard that the HD shocks raise your car a little but not the sport. so what
the heck?? could it be because of my sport packaged shocks that made it
lower before i had the bilsteins?? or could the shocks be HD??

i'd ask my friend to make sure but he is on a trip for about a week and i'm
just DYING TO KNOW!! so if anyone has some insights on this PLEASE email 
me!!

thanks
paul
pault77@domain.elided
>>>>>>>>>>>>>>>

What you are experiencing is the gas pressure extension force from the 
shocks.
Some shock designs use gas pressure to prevent the hydraulic oil in the 
shock from cavitating/foaming during hard use.  The low gas pressure in a 
Sachs/Boge(OEM) does not present much if any lift.  However the high 
pressure gas in a Bilstein and others can create 80lb of extension force or 
more per shock.
To explain; If your spring rate is 160 lb/inch the change from a hydraulic 
or low pressure gas shock to a Bilstein (with an 80 lb. extension force) 
will raise the vehicle 1/2 inch on that axle.  Hence when you select 
Bilstein (high pressure) shocks the suspension tuner will need to 
select/design a spring that is 1/2 inch shorter to compensate for the shock 
extension force.  Some times this can be adjusted out by the use if thinner 
spring perch cushions or a strut with an adjustable spring perch.

HD vs Sport shocks:
My experience with HD and Sport shocks is that both HD and Sport shocks 
from a given manufacture will have about the same rebound rate(design 
criteria, spring rate & sprung weight @ wheel).  However the compression 
rate(design criteria, spring rate and unsprung weight @ wheel) on the sport 
shocks will be much higher(maybe as much as twice) than the HD shocks. 
 This is the contributing factor that makes the Sport shock ride so rough. 
 All other suspension components remaining unchanged a vehicle with Sport 
shocks will have a harsh Porsche performance ride and the vehicle with the 
HD shocks will provide a pleasant and agile BMW performance ride.

Rod...

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Rodney Moore
e-mail: m6bigdog@domain.elided

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