> > Im mixed up here.As the front tires experience sidewall flex,causing the
> > steering wheel to get tighter in relation to the amount of slip angle(self
> > aligning torque),then how can the steering go light when the fronts lose
> > grip?If the tire is sliding heavily,the slip angle is even greater,then the
> > self aligning torque should be even greater.But instead the self aligning
> > torque gets lighter.Sidewall flex is lessened???
> I think that aligning torque is an effect of
> the spinning of the tire, and doesn't relate
> directly to tire deflection.
spinning on deflections in the tread and suspension geometry.
This depends on the castor of the wheel. If the effective center of
the (sliding) contact patch is to one side of the axis about which the
wheel can pivot, there will be an aligning torque.
The following picture illustrates the case. Assuming the forces are
balanced in magnitude (they will be in a sliding car tire example),
the fact that they are offset will result in an into-the-page
(counterclockwise) torque.
^
|
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|
V
That's a little different. If the wheel is already aligned, then the
aligning torque from castor will be zero, and the wheel will not tend
to center (it already is). If the wheel is not aligned, it's the same
case as above. (assuming a non-zero castor)
---Jim