Double Wishbone Suspension - Explained

The Basics of Double Wishbone Suspension

Double wishbone suspension is a type of suspension system used in vehicles to provide stability and control during movement. The system consists of two arms, one shorter than the other, which work together to support the weight of the vehicle. In this setup, the upper control arm is shorter than the lower one, allowing for a more precise control over the camber angle of the tire.

The Camber Angle: A Key Factor in Suspension

When it comes to suspension, one of the most important factors to consider is the camber angle. The camber angle refers to the angle between the top surface of the tire and the vertical plane. When a vehicle hits a bump or goes around a corner, the body of the car rolls, which affects the camber angle. In a double wishbone suspension with equal-length control arms, this can lead to changes in camber angle, resulting in positive or negative camber on the outside and inside tires.

The Problem with Equal-Length Control Arms

When both control arms are of equal length, the camber angle remains the same when traveling in a straight line. However, when the body rolls around a corner, the shorter upper control arm causes induced negative camber, which can lead to reduced contact between the tire and the road surface. This is particularly problematic on turns, as it allows the outside tire to press flat against the road while the inside tire has more clearance.

Solving the Problem: Unequal Control Arms

To address this issue, engineers developed unequal-length control arms, with the upper arm being shorter than the lower one. By doing so, they created a suspension system that can maintain negative camber even when the body rolls around a corner. This results in maximum contact between the tire and the road surface, which is essential for stability and control.

The Benefits of Double Wishbone Suspension

Double wishbone suspension has several advantages. One key benefit is its ability to provide increased negative camber with roll. As the body rolls, the negative camber increases, allowing for better contact with the road surface. Additionally, this system can handle large deflections, making it ideal for off-road use. The versatility of double wishbone suspension lies in its design, which allows for a variety of configuration options.

Positioning of Components

One of the unique features of double wishbone suspension is its flexibility when it comes to component placement. The shock absorber and spring can be mounted either on the lower control arm or the upper one, allowing for customization based on the specific needs of the vehicle. This versatility makes it easier to adapt the suspension system to different driving conditions and terrain.

Application in Front and Rear Suspension

Double wishbone suspension is not limited to just rear suspension; it can also be used in front suspension systems, particularly those that require steering. By employing double wishbone suspension in both the front and rear of a vehicle, engineers can create a highly capable and responsive handling system.

The Downsides: Higher Cost and Complexity

While double wishbone suspension has many benefits, there are some drawbacks to consider. One significant disadvantage is its higher cost compared to other suspension systems. Additionally, this system requires more components than others, which can increase maintenance costs and make repairs more complicated. However, these trade-offs are often worth it for the exceptional handling and stability provided by double wishbone suspension.

Conclusion

Double wishbone suspension is a highly effective and responsive suspension system that has become a standard in the automotive industry. Its ability to maintain negative camber with roll, handle large deflections, and provide versatility make it an attractive option for vehicle designers. While there are some drawbacks to consider, including higher cost and complexity, the benefits of double wishbone suspension far outweigh its limitations. As engineers continue to refine this system, we can expect even more advanced suspension technologies that will further enhance driving experiences.