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Re: effect of inclined roll axis on handling?

To: jcreasy@perforce.com, nihal@berkeley.edu
Subject: Re: effect of inclined roll axis on handling?
From: smokerbros@aol.com
Date: Wed, 19 Jul 2006 18:25:01 -0400
<<

>The higher rear roll center 
>would help transfer weight off the inside rear wheel very quickly, and 
>thus help rotate the car since. 
 
this is the precise effect i am interested in, since it gives better turn-in 
and then steady state is tuned with bars and springs. >>
 
My understanding is exactly the opposite.  If the front roll center is below 
the rear, and the roll axis is made steeper (raising rear roll center or 
lowering front) the car tends to "tip over" onto the outside front in a corner, 
overloading it.  Lowering the rear roll center increases the distance that the 
center of gravity has over the roll center.  This increases its lever arm over 
the roll center, hence more body roll and weight pulled off the inside rear and 
transfered to the outside rear.  
 
<<  >you could just use the 
>standard weight transfer equations involving track width, lat accel, and 
>CG height. 
 
here is where i get fuzzy. i dont think we can consider the front and rear 
systems in isolation since they are coupled by the chassis. or at least, i dont 
have a good answer for those that say i cant :) 
 
is there a substantial effect on corner weights caused by the car twisting 
under roll due to the inclined axis? >>
 
Yes, that's the way I understand it.  If the weight transfers about an inclined 
axis, more of it transfers to the outside wheel at the low end of the axis.  A 
flat roll axis will produce weight transfer where the front and rear of the car 
are less related to one another.  
 
Charlie
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