Double wishbone suspension consists of two unequal-length V-shaped or A-shaped upper and lower control arms and strut-type hydraulic shock absorbers. Typically, the upper control arm is shorter than the lower control arm. One end of the upper control arm connects to the strut shock absorber, and the other end connects to the vehicle body, while one end of the lower control arm connects to the wheel, and the other end connects to the vehicle body.
Additionally, the upper and lower control arms are also connected by a link rod, which is also connected to the wheel. By connecting multiple pivot points, the entire suspension structure enhances the integrity of both the upper and lower control arms and the entire suspension system. In FWD vehicles, double wishbone suspension installed on the front wheels incorporates not only a drivetrain mechanism but also a steering mechanism between the upper and lower control arms, making its structure significantly more complex than that of rear wheels without a steering mechanism. The steering kingpin is determined by the connection position and angle of the steering knuckle with the upper and lower control arms, allowing the steering wheel to rotate around the kingpin and also move up and down with the lower control arm.
The connection point between the upper and lower control arms and the steering kingpin must both support the front wheels for steering and control the vertical movement of the wheels. However, due to the issue of unequal lengths between the upper and lower control arms, this presents challenges for double wishbone suspension design. If the length difference between the upper and lower control arms is too small, it can lead to excessive changes in track width when the wheels move vertically, accelerating outer tire wear; conversely, if the length difference between the upper and lower arms is too large, it can cause excessive camber angle during steering, leading to accelerated inner tire wear. Therefore, increasing the length of the upper and lower control arms can reduce changes in track width and control changes in camber angle.
Furthermore, the upper and lower control arms of double wishbone suspension can counteract lateral forces, allowing the strut shock absorbers to only handle the vertical movement of the wheels, thus providing excellent directional stability in corners. This is why the front suspension, often referred to as the 'King of Corners,' utilizes double wishbone suspension. When cornering, body roll is minimal, and the overall stability is exceptionally well maintained.
