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

To: James Creasy <james@thevenom.net>
Subject: Re: what if CG was same as roll centers' axis
From: "John J. Stimson-III" <john@harlie.idsfa.net>
Date: Thu, 26 Jun 2003 10:32:11 -0700
On Thu, Jun 26, 2003 at 09:46:37AM -0700, James Creasy wrote:
> 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, you ought to know weight transfer causes body roll, not the
other way around...

The weight tranfer when the car is in a steady condition is always the
same, because you have the torque between the sideways load on the
tires at the road surface and the CG being balanced by the vertical
forces of the weight transferred between the tires on each side of the
car.  If those forces aren't the same, then the car hasn't reached
steady state and *something* must be moving/accelerating due to
imbalance.

If the springs are stiff, the body roll is less.  If the suspension
geometry results in the roll torque being transmitted by rigid
suspension pieces and bypassing the springs, then the body roll is
zero.  The suspension is effectively infinitely stiff in roll when
resisting sideways forces.  That doesn't mean that it won't roll due
to vertical forces like sudden changes in the slope of the pavement or
hopping up and down in the driver's seat...

-- 

john@idsfa.net                                              John Stimson
http://www.idsfa.net/~john/                              HMC Physics '94

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