Understanding Vehicle Wheel Alignment: Key Angles & Adjustments

Posted on Jan 22, 2025 in Technology

Understanding Vehicle Wheel Alignment

Components: Command bars, adjustment tie rods, angular levers, and hinges.

Key Alignment Angles

  • Convergence (Toe): Measures the parallelism of wheels on the same axle, in millimeters or degrees.

  • Camber: The angle of the wheel’s vertical tilt, measured in degrees.

  • Departure Angle (Caster): The inclination of the steering pivot relative to the tire’s vertical axis.

  • Forward Angle (Kingpin Inclination): The pivot axis angle to the vertical, viewed from the side. Positive when the pivot extends beyond the tire’s footprint, negative when behind.

Pressure Regulation

Pressure Regulator Valve and Flow: Regulates oil flow for a constant value, preventing overpressure. Usually installed in the pump.

Wheel Alignment Procedure

  1. Check tire pressures (e.g., 2.2 bar front, 2.4 bar rear).

  2. Measure and adjust frame height if needed.

  3. Find the steering center by turning the wheel lock-to-lock and mark the center position.

  4. Mount the alignment equipment to the vehicle.

  5. Perform wheel runout compensation to account for tire deformation.

  6. Measure convergence, camber, caster, etc., for front and rear axles.

  7. Adjust the drive, starting with the rear axle, then the front.

Active Roll Stabilization (ARS)

ARS: A hydraulic system managed by an electronic control unit. It uses sensors to communicate with hydraulic motors, a pressure accumulator, and a hydraulic pump. The system adjusts stabilizer bar hardness via hydraulic pressure.

Additional Angles

  • Thrust Angle: The bisector of rear wheel convergence relative to the vehicle’s longitudinal axis. Positive to the right, negative to the left.

  • Setback: The angle between the car’s longitudinal line and the perpendicular axis. Measured in degrees or mm, mainly focusing on the distance between the front and rear axles.

  • Track and Wheelbase: Track is the distance between wheels on the same axle, measured from the wheel’s center. Wheelbase is the distance between wheels on different axles. Tracks can differ, but wheelbases are usually equal.