What does "Zero Thrust" mean in a vehicle?

I did not know what will happen if "Zero Thrust" is established in wheel alignment of vehicle until I have the experience actually. I could do that after eliminating all the artifacts preventing me to do. It took me as long as 20 years of period to know the results shown as below.

Driving impression under "Zero Thrust".

The vehicle goes straight without influence by the external disturbance from the tire tread surfaces.

Though the rudder pressures caused by the road inclination is felt and watched on the steering wheel, the vehicle does not change the running direction.

And the vector direction could be kept if the steering wheel is held firmly at the center position.

The steering center position while running is established automatically and tightly not by the driver's will but by the "Zero Thrust" characteristic condition.

Once upper center condition might be changed in coming across the turning phase, the transition to turning scenery is very natural and smooth, just pleasant and fun.

The information of the road surface condition, roughness and inclination from every tire tread is watched and felt independently through the steering wheel pressure.

It is not always necessary to keep straight running, just keeping at the center position is enough.

Because the vehicle does not change the direction, no excessive steering turning adjusting is necessary in "Zero Thrust" condition.

"Zero Thrust" vehicle will increase the number to run about as the driver's unconscious action, and any desire to replace it into new one will not spring out however sophisticated and fascinating newly designed model might be flicked by the manufacturers.

Warning here, the tendency to keep the same vector direction straight often causes sleepy, the phenomena resembles recent Lane Keeping system. This is why sleepy awake system is sold as a pair, I wanna put an emphasis on this point here.

Notes:

All the wheel alignment and axle construction scaling and adjustment is performed under the condition of physical property with plastic deformation and history phenomenon, "Hysteresis".

So, releasing all the internal stress is indispensable at all. There exist many compliance bushes and mainly hub bearings including lubricating grease that has viscoelasticity.

Moving the car forward and backward action by hand with a human energy is necessary for releasing internal stress not only the specific wheel but for all wheels, unleashing each other's tension.

Remember here, moving with motor and breaking is inhibited in this scenery. However hard task it may be, this employment must be done only by hand's action.

As a natural phenomena, scaling terminal point displaces as a matter of fact, the scaling board should be moved adequately in every scaling and adjusting phase.

Accumulating every step is the key to success, even a hand cut or omitting crucial step will cause error leading to failure and the lasting piled efforts will be in vain. Let's start from the beginning.

Pay attention on the weight distribution in the car as German Opel specifies to put 60 kg weight on the driver's seat while wheel alignment adjusting, depending on the most likely possibility of the specific condition.

Weight distribution is important because it affects on the datum within the range of few minutes angle value. The error caused by some different weight distribution is not ignored.

European Safety Standard specifies the tolerance of "Thrust Angle" withing 10 minutes angle value, so to speak "Allowable error". The vehicle specified within the value and one with establishment of "Zero Thrust" are in a different dimension.

As a recent sophisticated modern vehicle is fully computerized and the user is not permitted to enter inside now, so reducing and minimizing "Assembly tolerance" is the only residual way to concern ourselves with our own car deeply.