Definitions
1. The stability of the car when turning and the optimal position of the front wheels in space are determined by four basic angles, which are expressed in degrees (with the exception of the angle of convergence, which is expressed by a dimensional value obtained directly from measurements).
2. Camber is the angle formed by the plane of the wheel and a vertical line drawn through the center of the wheel and the contact area between the tire and the road surface, as viewed from the front or rear of the vehicle. At "positive" camber, the upper part of the wheel is shifted from the vertical away from the car, with "negative" camber, the upper part of the wheel is shifted from the vertical towards the car.
3. Camber is not adjustable and is for reference only. This angle can be measured with a special device. If the camber angle is out of specification, the vehicle should be taken to a workshop for inspection by experienced personnel, as the only cause of camber failure is wear or damage to suspension or body parts.
4. The caster angle is the angle formed by the caster axis of the wheel and the vertical through the center of the wheel and the tire-to-road contact area, as viewed from the side of the vehicle. At "positive" longitudinal inclination of the axis of rotation the axis of rotation is inclined in such a way that the line of the axis passes in front of a vertical line drawn from the center of the wheel, when viewed along the direction of the car.
5. At "negative" tilt, the axis of rotation passes behind the vertical drawn from the center of the wheel, when viewed along the direction of the car.
6. The caster angle is not adjustable and is for reference only. This angle can be measured on a special stand. If the angle of the longitudinal inclination of the axis of rotation differs from the norm, then the car should be handed over to a service station for inspection, since the cause of the camber disorder can only be wear or damage to suspension or body parts.
7. Pivot Angle (usually denoted SAI) - this is the angle formed between the axis of rotation and the line drawn through the center of the wheel and the area of contact of the tire with the road surface, when viewed from behind or in front of the car. This angle is provided by the suspension design.
8. Toe-in is the angle between the axle of the car and a line drawn through the center of the wheel in a horizontal plane. wheels "converge", if facing each other and "disperse", if facing in different directions along the course of the car.
9. The convergence of the front wheels is adjusted by rotating the tie rod ends, which changes the total length of both rods.
10. The convergence of the rear wheels is adjusted by rotating the eccentrics on the bolts of the rear suspension wishbones to the body.
Wheel alignment - check
Checking the wheel alignment requires the use of special equipment and sufficient experience, therefore, it is advisable to carry out this type of service at a service station.
Wheel balancing
This type of service is advisable to carry out in a car service or in a specialized workshop.