[torsen] Re: Re: Re: Re: "Correcting" understeer

Brendan Rudack rudack at ucsub.colorado.edu
Mon Jan 22 00:09:03 EST 2001

On Sun, 21 Jan 2001, Eric Fletcher S.O.C. wrote:

> Say it enough times and you'll believe it.....

Do we need to tap our heels together 3 times as well??!

The whole understeer-oversteer argument needs to be explained in terms of
the relative slip angles of the front and rear tires and moments applied
about the vehicles C.O.G. 

Scott, what I interpreted from your post is that
the "neutral" behavior you experience is a stable state.  By definition,
understeer is stable state cornering.  The steering angle of the front
tires indicate a smaller radius turn than the vehicle is following.
(The front tires have a larger slip angle than the rears)
Oversteer on the otherhand is an unstable state.  The car wants to spin
and the driver has to work to to maintain control.  Basically I am saying
that "neutral" is a poor word to use for stable state understeer, an
inherent design in our quattros. Schaemen Sie Scott. 

If we had a trans-am chassis engineer on the list that was worth a damn,
maybe this whole thread would be over by now...

Brendan Rudack
University of Colorado M.E.

> Scott J. wrote:
> > Interesting post.  When I drive my urq *or* my tqw with the center diff
> > locked, it understeers more than when it's not locked.  When I lock the rear
> > with the center locked, it understeers more.  When I drive beyond the limit
> > at the track, or take either car to Steamboat, they both drift "neutrally",
> > per Jani's posted description.  Does that mean the car isn't understeering?
> > I'm thinking the definition of a "drift" as Jani described it in a static
> > 60f/40r chassis, is understeer.  I'd think you can reduce understeer by
> > changing front tires,  but I don't buy into a "neutral" drift as presented.

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