[A4] Sport Spring on a Stock B5 quattro?

Doug Johnson ur-quattro at msn.com
Wed Mar 21 14:31:37 EDT 2007

Installing the sport springs with my stock B5q struts sounds like a less-than-good idea, thanks.
Rules to remember:
1. A spring resists force in proportion to the displacement across the spring &
2. A damper resists force in proportion to the velocity across the damper.
Shock absorbers exert force based on the velocity across them.  For example, you could push against an infinitely-long damper for ever, at any given velocity, and the force it resists with remains constant.  Increase the velocity, though, and the force increases in direct proportion.  (Note: Velocity equals the speed at which one end of the damper approaches or recedes from the other end.  
So, if the spring resists the force based on the displacement across the spring, a stiff spring will never allow a damper to see the same high velocity as a soft spring.
Thanks for your help in my decision!~ Doug

Date: Wed, 21 Mar 2007 09:33:13 -0700From: thejimrose at gmail.comTo: a4 at audifans.com; Brizax at aol.com; ur-quattro at msn.comSubject: Re: [A4] Sport Spring on a Stock B5 quattro?

Wouldn't the dampers tend to last a tiny bit longer with stiff springs, because they are not being going through as much of their travel when coupled with the stiffer springs?  :-)~ Doug
well, from what little i know, i don't think it works that way. the shock / strut / dampener is always dampening the motion of the spring, regardless of where it's at in it's stroke. it doesn't work 'more' or 'less' at either end. it's true that the shock wouldn't use as much of it's stroke since the spring is stiffer, but it's working harder since it's controlling a spring that's stiffer than it was designed to control and will thus wear out faster. 

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