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
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