Re: Wandering, Negative Steering Roll Radius?

["Graydon D. Stuckey" <graydon@apollo.kettering.edu>]

On Wed, 3 Feb 1999, Scott Mo. wrote:

> for thought and ask does a change in wheel offset/width alter this Negative
> Steering Roll radius enough to make the car more susceptible to wandering?

Yes.  Possibly, or if you change the offset in the right direction, it 
could even get better.

> NSRR places each front wheels pivot point outside the center of the tires
> axis. This has the effect of making the front wheels want to return to
> center-to turn in the direction opposite that of the pivoting force-even

Most modern automobiles have this "feature."

> Some other questions:
> The V8 and 1991 200TQ 20V have different front hubs (441-407-615C) than
> the 1989-90 200 (447-407-615B) which I believe moves the wheel out further?

I think I've heard that also.

> What is the over all effect with the 35mm offset 15X7.5 wheels used on the
> V8 and 91 200TQ 20V?

One would have to plot out the changes to determine if they changed the
negative steer radius.  If they changed the kingpin inclination angle,
that would affect it also.  I know they did this to the S4. 

This was part of the reason for the mulitlink front suspension of the 
A8/A4/A6.  With that design, the upper "virtual" ball joint is out by the 
rotor which allows them to make the negative roll radius larger.  The 
downside is that you have much greater potential for slop in the fornt 
suspension since you have twice the number of ball joints.  The A8 in 
particular is _very_ impervious to changes in road conditions.  I ran one 
at 100 mph on partially snow covered roads once.  It barely noticed the 
snow drifts across part of the road.  Wait a minute, did I say 100 mph?   
I'd _never_ do that on a public road without good reason.  :-)

Later,
Graydon D. Stuckey
No Audis!  :-(
Yet!  :-)