Front double wishbone suspension (with floating joints), the wheels rotate around the kingpin axis coming from the ball joint of the upper arm (point C) to the imaginary axis of rotation (point D), extending from the lower arm (ov). Crossing the kingpin axis and the road surface (point E) - offset in the car from the center of the wheel on the road (W point), which gives the kingpin offset. Compared to strut front suspension, double wishbone front suspension (with floating arm joints) has the technical advantages described below.
The moment of inertia about the axis of the kingpin is reduced due to the small displacement of the kingpin from the center of the wheel. This feature reduces the likelihood of slip and intense steering vibrations during braking, disruption of the smooth operation of the steering on a bad road and the influence of road roughness on the moment of resistance of the vehicle's steered wheels.
Kingpin offset amount (negative kingpin offset) optimized. As a result, the influence of the weight of the axle is not felt, and the steering is facilitated. In addition, straight-line stability is improved because the toe-in moment of the braking force counteracts the moment caused by road roughness and/or the difference in braking forces between the right and left wheels.
Pic. 4.3. Comparative suspension diagram - with a rack and wishbones: 1 - the axis of the king pin; 2 - kingpin tilt; 3 - displacement of the kingpin; 4 - displacement of the kingpin relative to the center of the wheel; 5 - the center of the wheel; 6 – imaginary turning point; 7 - front suspension with two transverse levers of high mounting; 8 - front suspension with a rack (626); 9 – front view; 10 – top view; 11 - front