The driver turns steering wheel to steer car in desired direction. However, if driver has to constantly operate steering wheel to keep car moving straight when driving on a straight road or when turning, driver will have to make a lot of effort to turn car, and driver will consume a lot of power. energy Physical and mental stress. To solve this problem and prevent premature tire wear, wheels are mounted on body (or chassis) at a certain angle in accordance with certain requirements. These angles are collectively referred to as "alignment".
Toe-in is a general term for angular relationship between front and rear axles, wheels, steering and suspension components.
Driving is easy thanks to proper wheel alignment. When driving in a straight line, driver only needs to slightly adjust steering wheel to keep it in a straight line, and only a small amount of effort is required when turning. In other words, when all angular relationships that make up "toe" are adjusted correctly, control becomes easy. But even if one of them is incorrectly adjusted, following problems can occur: difficult steering, poor steering stability, poor steering response, reduced tire life.
What are wheel alignment elements
Vehicle positioning angle includes toe, camber, caster, kingpin lean, steering angle, hold angle, driving angle, and tire grinding radius. The above angles and dimensions depend on vehicle's suspension system, tire drive system (front wheel drive front wheel drive or front wheel drive rear wheel drive, two wheel drive or four wheel drive) and steering system (manual or power steering). steering). Tuning these items can optimize steering control and stability, and extend component life. Usually only recommended angle for adjustment during maintenance is the toe value.
Toe-in is a measure of how far wheels turn forward or away from vehicle's center line. Another understanding of toe-in can be described as distance between fronts of two wheels compared to distance between rears of same two wheels. If wheels are perfectly parallel, then two dimensions must be equal, meaning that toe angle is zero degrees. Toe-in is considered positive if front of wheel is tilted inward towards center line. When wheel is tilted, toe angle is considered negative. Positive toe angle and negative toe angle are also commonly referred to as front wheel toe and front wheel toe, as shown in figure below.
The function of toe is to compensate for tire's tendency to roll in or out due to camber angle and road resistance to keep vehicle straight.
Camber is angle of tire relative to vertical baseline. When top of wheel is tilted outward, it can be said that camber is positive at that moment. When top of a wheel is tilted inward, it is said to have negative camber. Camber adjustment can affect vehicle steer and tire wear, as shown in figure below.
Various suspension and steering devices are designed to minimize tire tread wear and traction while vehicle is in motion by keeping wheels perpendicular to ground and moving in a straight line.
Incorrect camber settings can cause tires to wear too quickly or unevenly. Excessive positive camber will wear out outer surface of tire tread. This uneven wear occurs when outside of tread is loaded more than inside.
Excessive negative camber will wear inside of tire tread. When load on inside of tread is higher than on outside, it causes uneven wear.
Thief in law Caster ▼
The caster angle is angle that kingpin axis is tilted forward or backward. The caster angle is obtained by measuring angle between steering axis and vertical when viewed from the side.
Tilting back from vertical is called positive caster, and leaning forward is called negative caster. There is an intersection point between center line of steering axis and ground, as well as a center point where tire makes contact with road surface. The distance between these two points is called caster distance.
Caster angle can provide straight-line stability: if car has a positive caster angle, then when wheel is turned to left, left neck tends to drop (this is due to fact that neck rotating along axis rotates, which in turn is tilted). But since neck is attached to wheel assembly, and ground also prevents downward movement, neck does not actually move down, instead left knuckle is pushed up, which raises body a little. After steering is completed and steering wheel is released, weight of lifted vehicle causes knuckle to drop again. Thus, simply return axle trunnion to its original position to move straight ahead.