Max is right on most counts and I leave the calculation of the
lever shock valve amplification problems to the Hydraulic gods.
But the lever does not support any of the weight of the car. It
does however take some smaller share of lateral road forces thru
the bushings (that the lever is mounted in) and yes this is
exactly where most lever shocks fail - in the leak mode.
The Macpherson strut or tube shock works on a well located A arm
and is spared the side forces.
Mike L.
60A,67E,59Bug
----- Original Message -----
From: Max Heim <mvheim@studiolimage.com>
To: MG List <mgs@autox.team.net>
Sent: June 9, 2000 1:41 PM
Subject: Re: Fw: Tube shock conversion data
> Actually, the feature of lever shocks which I always found
dubious was
> their mechanical "dis-advantage", so to speak. On the long end
of the
> lever you have the weight of the car, and all the forces acting
upon it.
> On the short end you have this tiny little valve body. The
forces on the
> valve body as amplified by the long lever arm must be enormous.
> Conversely, any action produced by the valve body (i.e. damping)
is at an
> enormous mechanical disadvantage vis-a-vis the rest of the car.
In
> comparison, the forces on the tube shock are operating "straight
through"
> the axis (or slightly deflected if it is not mounted absolutely
> perpendicularly), with no leverage advantage either way. This
probably
> enables lower internal hydraulic pressures, which would explain
why leaky
> tube shocks are rare, but leaky lever shocks are normal. But it
also
> suggests that tube shocks, with longer travel and lower
pressures, could
> be designed to have more subtle, even non-linear, damping
action.
>
> All of the above is pure speculation, of course... <g>
>
> >
> >In a message dated 6/8/00 8:09:45 PM Eastern Daylight Time,
yd3@nvc.net
> >writes:
> >
> ><< I believe I have read somewhere that the there are several
> > reasons most vehicles went to tube shocks.
> >
> > 1) cost:
> >
> > 2) response: To my mind, the lever shock would have more play
> > between jounce and bounce because of the design and rocking
> > factor. It would be similar to determining TDC in an engine.
A
> > piston could be TDC while the crank could be rotated a few
> > degrees with showing any piston movement. Thus the lever has
> > some "dead" spots between jounce and bounce.
> >
> > 3) heat: I would think the tube shock is less sentive to heat
> > retension.
> >
> > 4) travel: I would think the tube shock's greater travel would
> > produce more uniform results. >>
> >
>
>
> --
>
> Max Heim
> '66 MGB GHN3L76149
> If you're near Mountain View, CA,
> it's the red one with the silver bootlid.
>
>
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