What Is An Aligner; Characteristic Angles; Camber; Caster - SICE A 926 Manual De Instrucciones

WHAT IS AN ALIGNER

An aligner or wheel aligner is defined as a measurement instrument detecting the characteristic
alignment angles of a vehicle.
An aligner consists of a central unit and two or four measuring heads to apply to the wheels of the
vehicle.

CHARACTERISTIC ANGLES

1) TOE (Fig. 35 and fig. 36)
Toe is the angle between the equatorial plane of the wheel and the axis of symmetry or the
thrust axis of the vehicle.
The axis of symmetry is an imaginary line that divides the car into two halves longitudinally; the
thrust axis is the direction of travel of the rear axle.
The unit of measurement for toe values is degrees or millimetres.
2) CAMBER (fig. 37)
Camber is the angle between the equatorial plane of the wheel and the vertical plane; camber is
positive when the upper part of the wheel is angled away from the vehicle.
The unit of measurement for camber values is degrees.
3) CASTER (fig. 38)
Caster is the angle formed between the vertical and an imaginary extension from the steering
axis on the longitudinal plane of the vehicle (longitudinal upright angle).
Caster is measured with the wheels turned.
The unit of measurement is degrees.
4) KING PIN ANGLE (fig. 39)
This is the angle formed between the vertical and the extension of the steering axis on the
transverse plane of the vehicle (transverse upright angle).
The king-pin angle is measured with the wheels turned.
The unit of measurement is degrees.
5) TOE-OUT ON TURN (fig. 40)
Steering angle toe difference on the front wheels. The unit of measurement is degrees.
6) SET BACK (or misalignment of wheels on the same axle) (fig. 41)
This measurement shows the difference in position of one wheel with respect to the other on the
perpendicular of the longitudinal axis of the vehicle.
Set back is measured on the front and rear axles of the vehicle; although rear set-back must not
be confused with the thrust angle.
The unit of measurement is degrees.
7) THRUST ANGLE (fig. 42)
This is the angle formed between the axis of symmetry of the vehicle and the direction of travel
of the rear axle.
The unit of measurement is degrees.
15