Uneven caster side-to-side creates too much cross-caster that can make a vehicle pull or lead towards the side that has the least (negative) caster. The underlying cause may be a bent strut, spindle or mislocated strut tower.

Does thrust angle cause a pull?

A positive thrust angle will try to steer the vehicle to the left, while a negative thrust angle will try to steer the vehicle to the right. This will cause the driver to pull the steering wheel right or left to compensate.

What is the result of adding SAI and camber angles?

SAI is the measurement in degrees of the steering pivot line when viewed from the front of the vehicle. This angle, when added to the camber to form the included angle (see below) causes the vehicle to lift slightly when you turn the wheel away from a straight ahead position.