> -----Original Message-----
> From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
> Behalf Of RossOvercash
> Sent: Monday, August 10, 1998 8:32 AM
> To: Barney Gaylord; mgs@autox.team.net
> Subject: RE: Why new leaf springs may be a waste
>
>
> So the point is if it ain't broke and it's working just fine and you are
> getting good results don't fix it! Or maybe bbecareful what you wish for
> because once you get it you may not be happy.!!
>
> I enjoyed your logic, put the springs back on and see what
> happens, they are
> stock just worn stock! No one complained when you increased your
> ride hight
> did they?
Unfortuneately, most shop manuals list a ride height spec, and that's what
the SCCA goes buy, even OE springs are illegal if they sag below the spec...
>
> Safety Fast!!
>
> Ross Overcash, 74B, NAMGBR 2-1172, Ayer, MA
> http://www.tiac.net/users/jroverca/index.htm
>
> > -----Original Message-----
> > From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
> > Behalf Of Barney Gaylord
> > Sent: Sunday, August 09, 1998 9:34 PM
> > To: mgs@autox.team.net
> > Subject: Why new leaf springs may be a waste
> >
> >
> > Lots of us like to special tune our engines for a bit of extra zip. And
> > tires and springs and sway bars are frequently kicked around
> this list in
> > the interest of better handling. So let's see if suspension tuning can
> > tickle a serious note here.
> >
> > This recent discussion of lever shocks and suspension travel
> > reminded me of
> > a problem I have encountered with my MGA new leaf springs. Bear in mind
> > that the front rebound buffers and the rear rebound straps are
> > necessary to
> > prevent damage to the shocks from over extension on airborn bounce.
> >
> > I've been autocrossing my MGA rather seriously for several years now.
> > Stock class in SCCA allows only a select few changes to original
> > equipment,
> > among these are:
> > (1) any DOT approved tires (has a tread patteren - not slicks)
> > (2) any front anti-sway bar
> > My current setup uses road racing tires with soft rubber compound on the
> > track, and a 3/4" front sway bar packed tightly with polyurethane
> > bushings.
> >
> > A couple years ago I had this package doing marvelous things,
> was winning
> > regularly with SCCA, sometimes taking the event index trophy
> (ask later).
> > The car had neutral handling on the road with standard radial
> > tires (ala VW
> > Beetle), and a little oversteer on the track with the race tires,
> > very nice
> > for autocrossing.
> >
> > Early spring last year I was preparing the car for Brit Run to the Sun -
> > Alaska '97, and I thought it was a good idea to install new leaf
> > springs to
> > regain some ground clearance lost to nearly four decades of
> > gradual sagging
> > of the rear springs. So I did. And the trip was fantastic.
> But when the
> > car returned to the track it had a rather dramatic change in
> personality.
> > So here's the problem.
> >
> > The new springs make the body sit higher at the rear, as was
> intended. So
> > now the rear axel has more upward travel available to the rubber frame
> > bumpers, but less downward travel available before it hits the maximum
> > length of the rebound straps. Sticky race tires on the car
> will induce a
> > certain amount of body roll in hard cornering, in spite of the
> heavy front
> > sway bar. As the car is approaching the limit of adhesion in hard
> > cornering, the body roll gets to the point where the inside rear fender
> > lifts until the rebound strap is stretched completely tight. At
> > that point
> > the rear roll stifness suddenly transitions to infinity. Then
> with just a
> > little more body roll the inside rear wheel gets lifted right off the
> > pavement.
> >
> > Now the car is running around on three wheels, and no matter what the
> > spring rates, stiffness, shocks or sway bars are doing, the one outside
> > rear tire is carrying about half the weight of the vehicle.
> That relative
> > extra loading of the tire reduces its grip efficiency a bit,
> and the rear
> > end lets loose and swings wide putting the car into a sever case of
> > oversteer. Now I can generally get a handle on it (hang it
> sideways) and
> > keep it from looping, but, it cannot corner any faster because
> of the loss
> > of latteral traction, and it cannot accelerate because one
> drive wheel is
> > in the air (open differential). Grrrrrrrr.
> >
> > This is precisely why most of our beloved LBCs will benefit
> substantially
> > from a large front sway bar, the rear suspension is WAY too
> stiff. I was
> > thinking that a LARGER front sway bar might help, but some
> friends tell me
> > that the inside rear wheel is sometimes four inches off the pavement!
> > Yikes! Stiffer front springs and softer rear springs may be in
> order, but
> > in Stock class one is not allowed to change the springs from the stock
> > part. Right about now I am seriously considering reinstalling the old
> > sagging rear springs. Maybe nobody will notice and file a protest about
> > changing the ride height. If they do, my car could get kicked
> into Street
> > Prepared class, and I'm definitely not "prepared" for that.
> >
> > So waddaya think folks? Is this stuff worth a few cells af gray matter?
> >
> > Barney Gaylord
> > 1958 MGA with an attitude
> >
> > PS
> > If you want to get a good handle on handling, read How To Make Your Car
> > Handle, by Fred Puhn.
> > BG
> >
> >
>
>
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