Pneumatic trail

[fastback33]

So, let me get this straight. The further your aligning moment is from the actual center of the tire contact patch, is basically how you as a driver are able to "sense" the tires breaking away? And form this as you increase slip angle you are going to get the aligning torque closer to the contact patch, allowing you to feel the tires load sensitivity? Which in turn warns you that the tires are falling off at some degree of slip angle correct?

been reading milliken again, and im on a mission.

[Jersey Tom]

Eh.. kinda but not really. Aligning torque does start high and then falls off as the tires work harder and the effective lateral force vector moves closer to the center of the tire footprint, yes. But, aligning torque always falls off before the tire peaks, so you can't quite feel where the limit is.

Even on a road car, going around something like an on ramp.. you can sense where the limit is just intuitively.. where as you're tugging at the wheel the car stops gaining any yaw rate and the front end response is nearing zero.

Don't know what you mean by the load sensitivity bit. You can feel load sensitivity pretty easily when you lift off the throttle and the car wants to pivot.

[speedsense]

Eh.. kinda but not really. Aligning torque does start high and then falls off as the tires work harder and the effective lateral force vector moves closer to the center of the tire footprint, yes. But, aligning torque always falls off before the tire peaks, so you can't quite feel where the limit is.

Even on a road car, going around something like an on ramp.. you can sense where the limit is just intuitively.. where as you're tugging at the wheel the car stops gaining any yaw rate and the front end response is nearing zero.

Don't know what you mean by the load sensitivity bit. You can feel load sensitivity pretty easily when you lift off the throttle and the car wants to pivot.

shouldn't this statement be- "..the Aligning Torque Peaks early and falls from there, and the "breakaway" point of the tire is on this declining slope"...?

However, there is a point where it does start high- The highest point of aligning torque, can be experienced on a stationary tire (full weight of the car), and without rolling forces. Add in steering input. It has been noted, that this actually the highest "grip" that the tire will ever achieve (excluding down force). Introduction of rolling forces and tire contact patch contortion,to name important and major aspects of many, only subtracts from this aligning torque number.
If I were able to take a stationary tire (weight of car included) and twist a slip angle into the tire (right up to breakaway), I could form a slip angle that is far greater than the one that is created with the car at racing speeds and on the limit of adhesion (same tire, same car). This due to the added forces acting on the tire.

I too am confused at Fastback33's comment of load sensitivity as the statement can mean a few things. It appears that FB means sensitive to steering input and the driver's feel of it.
Involving driver feel opens a literal can of worms.
As JT points out an under steering moment of the front wheels, if you take two different drivers, one may say that the car has too much understeer, based on "feel" while the other may say it's neutral, again based on "feel".
In data acquisition it is possible to "see" aligning torque feel by adding strain gauges to the steering column or the tie rods, and measure the aligning torque (against lateral g for that end of the car) "feel" in pounds or Neutons. Though more importantly converting that number to a frequency shows more of the technique of the driver (tires are frequency dependent).
A driver with very aggressive tendencies will enact higher frequencies through his responses to aligning torque in his steering input. A driver with much lower aggressiveness (read smoother) will have very low frequencies in steering input. Yet both feel the exact same aligning torque (if they drove the same car) and both will achieve the limits of adhesion through out a corner, if they are truly great drivers. Villenvue Sr vs Lauda for instance.