Ackerman Steering Geometry and Anti Ackerman

Summary

This video dives into the concept of Ackermann steering geometry and its racing variant, Anti-Ackermann. The host explains how Ackermann geometry ensures that inside and outside front tires follow the correct circular paths during a turn. The video also touches on the role of slip angles in optimizing tire grip, especially under high loads, and how race cars adjust steering geometry for high-speed corners. Additionally, an update is provided on a project car (likely a Mercedes-Benz E55), which is undergoing tuning and boost adjustments for maximum power. A fascinating look at car handling dynamics, with insights on both street and racing vehicles.

Takeaways

• 😀 The video covers Ackermann steering geometry and provides an update on the e55 project, which is currently on hold but is resuming work with an AMF ic8 installation.
• 😀 Ackermann steering geometry ensures that the inside tire turns more than the outside tire when a vehicle is turning in a circle, allowing the tires to follow their respective circles without scrubbing.
• 😀 To achieve Ackermann geometry, the steering knuckles are angled slightly inward so that imaginary lines drawn through the steering axis and the ball joint intersect at the center line of the rear tires.
• 😀 In racing, cars may use an opposite steering geometry known as anti-Ackermann, where the outside tire turns more than the inside tire, which is often used to optimize grip on high-speed corners.
• 😀 Slip angles describe the difference between the direction a tire is pointing and the direction the car is actually traveling, and understanding this concept is essential to understanding Ackermann and anti-Ackermann geometries.
• 😀 The optimal slip angle for a tire depends on the load: tires under higher load require a greater slip angle to maintain maximum grip, which is crucial in racing to ensure both inside and outside tires have the best possible grip.
• 😀 In high-speed corners, the outside tires are under greater load and need to be at a higher slip angle than the inside tires, which is why anti-Ackermann geometry is used to optimize grip in such scenarios.
• 😀 The video uses diagrams to show how Ackermann and anti-Ackermann geometries affect the direction the tires should be pointing based on slip angles, emphasizing the need to adjust geometry for different types of corners.
• 😀 Anti-Ackermann geometry works well for high-speed, sweeping corners (like those in Formula 1 or IndyCar), but can be ineffective or even detrimental for tight, low-speed corners due to excessive tire misalignment.
• 😀 Racing teams may adjust their suspension and steering geometry between tracks to optimize performance based on the specific demands of each circuit, demonstrating the flexibility and adaptability needed for different track conditions.

Q & A

What is the purpose of Ackermann steering geometry?

The purpose of Ackermann steering geometry is to ensure that when a car turns, the inside front tire follows a smaller circle and turns more than the outside front tire, allowing the car to follow the correct path without tire scrubbing.

How is Ackermann steering geometry achieved?

Ackermann steering geometry is achieved by angling the steering knuckle slightly inwards, so that if you draw lines through the steering axis and ball joint, they intersect at the center of the rear axle.

Why is Ackermann steering geometry important in production cars?

In production cars, Ackermann steering geometry is crucial because it helps the tires follow their correct path during turns, preventing unnecessary tire scrubbing, which improves handling and reduces tire wear.

What is Anti-Ackermann geometry, and when is it used?

Anti-Ackermann geometry is the opposite of Ackermann steering, where the outside front tire turns more than the inside tire. It is used in racing cars, particularly in high-speed circuits, to optimize grip during sweeping corners.

How do slip angles affect tire grip?

Slip angles refer to the difference between the direction the tire is pointing and the actual direction the car is moving. A small slip angle helps the tire maintain optimal grip, but beyond a certain angle, grip decreases.

Why do racing cars use Anti-Ackermann geometry?

Racing cars use Anti-Ackermann geometry to optimize the slip angles of the tires. In high-speed corners, the outside tires are under more load and need a greater slip angle to maintain maximum grip, which this geometry supports.

What is the role of load in determining the optimal slip angle of a tire?

Tires under higher load, such as the outside tires in a corner, need a greater slip angle to maintain maximum grip, whereas tires under lower load, like the inside tires, need less of a slip angle.

How does Anti-Ackermann geometry work in tight corners?

In tight corners, Anti-Ackermann geometry doesn't perform well because the outside tire turns too much and the inside tire too little, leading to poor grip and potentially less effective handling.

How do racing teams adjust Ackermann geometry for different tracks?

Racing teams adjust the Ackermann geometry depending on the track's characteristics. For tracks with more high-speed, sweeping corners, Anti-Ackermann might be preferred, while tracks with tight corners may use a more conventional Ackermann setup.

What is the current status of the E55 project mentioned in the video?

The E55 project was paused for the winter but has resumed. The twin-turbo system is complete, and the next step is installing an AMF IC8 and tuning the car to increase boost levels, with a follow-up video expected in mid to late April.