Quote:
Originally Posted by ram  Actually on the contrary the car will stand tall and level only when the front wheels are pointing straight ahead.
At any other angle the car will stoop down.
Why?
Cars have positive castor (like hospital bed wheels), to get them to automatically straighten out after completion of a turn. However, the positive castor is achieved by tilting the kingpin axis rearward.
This causes the entire front end to stoop when the wheel supporting it up is steered. Haven't you seen a motorcycle lower its front when you steer the front wheel while locking the handlebar?
Look at the geometry in the figure. 
There's more!
As each front wheel deviates by a different angle with the direction of the car, the two front corners will stoop down by different extents.
In fact, the corner inside the turn will stoop more than the outer corner.
Ram |
On a bike the stooping is caused by the reduction in the distance between the wheel-ground contact and the ground contact of the steering axis. When the wheel is totally turned perpendicular the distance is zero, hence the wheel center moves down and the upper portion stoops down.
However, in this case the steering axis, is coincident with the wheel-centerline. Not applicable to cars.
In case of a car with the wheel centerline being offset (at the point of suspension), just because of the positive caster, the trailing side lowers and thus pushes the ground below, and the car rises up. Now due to the caster settings and the fact that the wheel center line is outwards from the wheel center-line, the outer wheel center rise and inner wheel center lowers. The car stays lowest at dead ahead position and thus increases its tendency to keep straight ahead with no forces on the steering.
The difference in lateral angle while steering is due to the Toe settings, the inner wheels turn more than the outer wheels.
I can explain the same diagramattically but the super-computer that I am posting this from does not even have a basic paint!!