In this Blog, You will learn about what camber is and how positive and negative camber affect a vehicle's road handling. Additionally, we will also discuss the significance of steering axis inclination and scrub radius.
The Importance of Wheel Alignment
Wheel alignment refers to the adjustment of various suspension components in order to position the wheel at specific angles, thereby enhancing the overall handling, tire wear, and performance of the vehicle. These alignment angles can also be modified to achieve distinct handling characteristics. In certain cases, such as motorsports and off-road applications, wheel alignment may be adjusted beyond the typical range for specific reasons.
The primary purpose of wheel alignment is to prevent the vehicle from pulling to one side and to avoid premature wear on the rear tires, steering, and suspension parts. Ultimately, it ensures optimal road handling. Wheel alignment involves various primary and secondary angles that are associated with this process.
The concept of camber, which refers to the angle of the tire or wheel concerning the vertical position as observed from various points on the vehicle. It's worth noting that camber angles are typically minute, but for the purpose of this discussion, we will exaggerate them.
Benefits of having Positive Camber and Its Impact on Road Handling
Positive camber, as defined, denotes the tilt of the wheel's upper part away from the vehicle. Conversely, negative camber describes the top of the wheel tilting towards the vehicle. In most cases, positive camber is applied. The rationale behind this choice can be understood by examining the steering axis inclination, also known as the kingpin inclination (KPI). The KPI represents the angle formed by the axis that passes through the outer ball joints of the upper and lower wishbone and the vertical plane.
Visualize a cut section of the front of a vehicle: the upper and lower wishbones are connected to the X axis, while the steering knuckle, also referred to as the upright, is present. The axis which passes through the outer ball joints of the upper and lower wishbone is termed the steering axis or kingpin axis. The angle formed by this axis and the vertical plane is known as the steering axis inclination or kingpin inclination.
This axis is crucial as it determines the direction in which the wheels steer. Any input applied to the steering wheel will result in scrub, occurring at the bottom of the contact patch. The distance between the vertical line and the steering axis is referred to as the scrub radius. A large scrub radius translates to increased driver effort at lower speeds. To alleviate this issue, a combination of steering axis inclination and positive camber is employed.
By adjusting the desired positive camber to a small degree, the scrub radius reduces from s1 to s2, where s2 is lower. As the scrub radius decreases, driver effort diminishes during low-speed turning situations. It's important to note that the scrub radius can be positive, negative, or zero based on the designer's requirements. Additionally, positive camber generates self-aligning torque, causing the wheel to push against the ground. The reaction forces then strive to return the tire to a straight position, thus ensuring stability.
The Benefits of Negative Camber and its Impact on Road Handling
The advantages possessing a negative camber are illustrated in this description. In this scenario, the width of the tire ensures full contact with the ground, enabling it to have ample traction. Additionally, the load is evenly distributed.
Therefore, having a neutral camber, where the tire remains vertical, is beneficial for maintaining stability on straight roads. However, a different scenario arises when the car makes a right turn. causes an increase in load on the outer tire results in body roll. As a consequence, the outer tire tilts, reducing its contact area with the ground. Consequently, traction during turning is diminished. To counter this issue, a certain amount of negative camber is required for the tire. This adjustment increases the contact patch of the tire while turning, thereby enhancing traction, which is the desired outcome.
However, it should be noted that in doing so, the contact patch of the inner tire decreases significantly. Nevertheless, this is not a major concern since during turning, the majority of the vehicle's weight is situated on the outer tire. As such, sacrificing some traction on the inner tire is acceptable.
Negative camber also produces camber thrust which will help the vehicle while turning by providing extra inward force having negative camber will surely help while cornering but during straight driving negative camber will cause the excessive heating of the inner boundary of that which will increase the diarrhea as negative camber produces camber thrust so if one tire hits a bump or loses traction it will lead to the sliding of waken which will affect the road handling so having negative camber is good for turns and for straight also if you are ready to compromise some straight-line acceleration on the acceleration.
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