autox
[Top] [All Lists]

Re: Coil Over Spring Rates

To: autox@autox.team.net
Subject: Re: Coil Over Spring Rates
From: Kevin Wenzel <kwenzel@rmsolo.org>
Date: Wed, 11 Oct 2000 09:51:35 -0600
At 04:54 PM 10/10/2000 -0700, Ian McCloghrie wrote:
>On Oct 10, 2000 Paul Foster wrote:
> > You might change the range of travel by using a larger or smaller
> > spring, but I don't see how you are changing the lever arm unless you
> > move the mounting points.
>
>Converting a car that previous did not have a coilover suspension to
>one that does (which I believe the original poster was doing?) almost
>certainly moves the mounting points. :)

Changing the position of the upper and/or lower mounting points of a spring 
along the same axis that the original spring defined (which will be the 
case in a McPherson strut design, unless you move the spring mounts away 
from the strut... which is a bit more than a coilover conversion) will 
*not* change the ratio between spring rate and effective spring rate (which 
is usually pretty close to 1:1 in a strut situation, anyway).  If you alter 
the angle at which the strut is connected to the upright (or otherwise 
change the relationship between the bottom of the strut and the ball joint 
at the outboard end of the lower suspension link), then a line drawn 
through the center of the spring will intersect the lower suspension link 
at a different distance (from the point at which a line drawn from the top 
of the strut to the ball joint intersects with the same link) than stock, 
thus altering the effective spring rate - but simply altering the position 
of the lower spring mount along the strut body won't do anything to that 
measurement...

In the original poster's case, 166# is 166#.

--
Kevin Wenzel
kwenzel@rmsolo.org
EP 117


<Prev in Thread] Current Thread [Next in Thread>