[asphaltgambler]

Several things in play geometry-wise that sets this in motion. First when the manufacturer is designing the proper front end geometry tire size, wheel offset, intended use. For off road - 4 wheel drive vehicles very little caster and negative camber is used, especially in straight axle applications as it makes steering difficult at low/ no speeds.

Also there is a "point of intersection" - vertically speaking where talking the above angles - factoring distance between the spindle and where the center of the tire contact patch hits the pavement.

By adding ( or subtracting) wheel and tire diameter, adding ( or subtracting) wheel off set - then adding unsprung weight as well as rotational weight can and will cause this.