The verticality of the two rear wheels is inconsistent.

The rear wheels are not perpendicular to the ground as follows:

The wheel surface is not perpendicular to the ground, and the angle between the wheel and the vertical line of the ground is called camber. There are two kinds of surfaces. If the tire is splayed, it is called negative camber, while if it is V-shaped, it is called positive camber. Different angles can change the contact point and stress point between the tire and the ground, which directly affects the grip and wear of the tire. The stress distribution of the vehicle weight on the axle is changed to avoid abnormal wear of the bearing. In addition, the existence of camber can be used to offset the angle change caused by the deformation of suspension system parts and the gap between movable surfaces after the car body is loaded.

Negative camber angle

The number 8 is what we call negative curvature. This design is to obtain better curve performance. The car will roll when turning, and the outer wheel and suspension will be compressed. At this time, the outer wheel with negative inclination will become a positive inclination (perpendicular to the ground) in exchange for better grip of the tire in the corner.

Positive camber angle

"V" is the positive camber angle, which is generally recognized as the "V" after the car is lifted. When the car is empty and the wheels touch the ground, the tires are basically perpendicular to the ground. When the car is fully loaded, it will show a "V" shape. The purpose is also to make the car have better grip when turning.