RE: what if CG was same as roll centers' axis

["Rick Brown" <rbrown7@covad.net>]

Weight transfer depends only on the ratio of the cg height to the track.  As
Larry pointed out, adjusting the roll axis relative to the cg only
determines what portion of weight transfer arises from the moment of the
sprung mass on the roll axis and what portion aries from purely lateral
translation of the sprung mass on the roll center.  The third portion is the
weight transfer of the unsprung mass which is relatively less than the other
two.  Still, the total weight transfer only depends on the cg height and the
track.

--- Rick Brown
    BP Corvette

-----Original Message-----
From: owner-ba-autox@autox.team.net
[mailto:owner-ba-autox@autox.team.net]On Behalf Of James Creasy
Sent: Thursday, June 26, 2003 9:47 AM
To: Larrybsp@aol.com
Cc: ba-autox@autox.team.net
Subject: Re: what if CG was same as roll centers' axis


so there would still be weight transfer?  why?  assuming stiff sidewall,
there
is no body roll, so wouldnt all the tires still be loaded evenly?  thus no
weight transfer.

james
  ----- Original Message -----
  From: Larrybsp@aol.com
  To: james@thevenom.net
  Cc: ba-autox@autox.team.net
  Sent: Thursday, June 26, 2003 9:33 AM
  Subject: Re: what if CG was same as roll centers' axis


  Ifrom:larrybsp@aol.com (Larry Stark)



    if you lowered the CG of a car to the point where it was on the line
    connecting the roll centers, what would happen?  you would not have any
body
    roll and so you wouldnt need sway bars.




     James,
                 With the CG on the roll axis there will be no body roll and
you would  have instant weight transfer as you turned the car. The effect
would be like having no springs at all. The centrifical force of the turn
would transfer weight from the inside to outside tires in direct proportion
to
the rise in centrifical force and the track.



    conversely, if you raised the roll centers so you intersected the CG,
what
    would happen?



          The effect would be the same.

           You do not want instantaneous weight transfer. It rapidly loads
the
outside tire and is a very unstable condition. Its like driving on your bump
stops. In a sharp turn like an autocross the tire would probably lose
traction
immediately. If you want to drive a car like this get a Go Kart. Then again
thats what you drive now:):):):).


           Larry



    my feeling is neither of these works well, but why?

    james