Strust vs. Shocks (was Re: Need Struts)

[George Roffe]

Ben Missele wrote:

>Geo Wrote:

> > With a MacPherson strut, the upper locating or pivot point is
> > where the shaft attaches at the shock tower.  <snip> The top
>of
> > a strut not only turns, but it pivots as well.

>  I'm guessing that the second sentence is supposed to say shock
>instead of strut. So, going by this, wouldn't it mean that a B13
>has struts on the front and rear? I've had the struts out of my
>car a few times and as far as I can tell, they don't pivot at
>the top. I must be missing something.

Yep.  You're missing something. :-)

The top of the strut must allow a bit of movement while the suspension
swings through its arc.  If it did not, the suspension could not move.

In fact, a B13 *does* have struts on the front and back.

I think you are confusing turning with pivoting.

Do this....

Using map pins (or whatever works for you) and pin a length of paper at one
end (simulating a lower control arm).  Draw a dot above it some distance
(probably best if it's the same as the length of paper).  Draw a dot at the
end of the length of paper.

Now, move the length of paper through an arc, stopping at various points
along the way.  Heck, you could even draw a line between the dots.  You
will find that the lines don't match up.  The change in position of those
lines simulates the motion a strut goes through and thus you can see that a
strut pivots at the top.

For extra credit you could really simulate a strut including the attachment
points.  You could visually see the camber change that occurs.

For Suspension 102, read Tune to Win.

George Roffe
Houston, TX
91 SE-R (well modded)
91 G20 turbo (well modded)
84 944 SCCA ITS race car under construction
<http://home.earthlink.net/~geo3/>