A technician is performing an alignment on a vehicle and observes that the front left Included Angle (IA) is 25.0 degrees and the front right IA is 23.0 degrees. The specification for Included Angle is 24.0 +/- 0.5 degrees. The front left camber is -1.0 degrees and the front right camber is +1.0 degrees. What is the MOST likely cause of the IA discrepancy?
- AA bent spindle on the left front wheel.
- BExcessive positive toe on the right front wheel.
- CA bent spindle on the right front wheel.
- DIncorrect caster settings on both front wheels.
Show answer & explanationAnswer & explanation
Correct answer: C. A bent spindle on the right front wheel.
Included Angle (IA) is the sum of SAI and camber. Since SAI is non-adjustable and fixed by design, if IA is out of specification and camber is also out, it can indicate a bent spindle. The right front IA is 23.0 degrees (spec 24.0 +/- 0.5), and its camber is +1.0 degrees. If SAI was theoretically 23.0 - 1.0 = 22.0 degrees, it would be significantly different from the left's assumed SAI (25.0 - (-1.0) = 26.0 degrees). A bent spindle primarily affects SAI and thus IA. A lower IA on the right (23.0 vs 25.0) and a positive camber (+1.0) suggests the spindle is bent in a way that reduces SAI and pushes the top of the wheel out.
Why the other options are wrong
- A. A bent spindle on the left front would likely cause its IA to be out of spec, but the right front is the one outside the range (23.0 vs 24.0 +/- 0.5).
- B. Toe is a horizontal angle and does not influence the vertical angles of Camber or Included Angle.
- D. Caster does not directly affect Included Angle or Camber; it influences steering returnability and effort.
Included Angle (IA) Discrepancy Diagnosis
Significant deviations in Included Angle, especially when accompanied by out-of-spec camber, often point to a bent spindle or steering knuckle, as SAI (part of IA) is non-adjustable.
- IA = SAI + Camber.
- SAI is fixed by design.
- IA issues imply damage if camber cannot explain it.
Memory trick: IA + Camber = SAI, if IA is off, check for bent metal.