Ackermann steering geometry — wheel angles during a turn When a vehicle turns a corner, which statements about the front wheel angles are true?

Difficulty: Easy

Correct Answer: all of the above

Explanation:


Introduction / Context:
Steering linkage geometry is designed so that both front wheels roll without scrubbing during a turn. This is achieved by creating different steering angles on the inside and outside wheels. Understanding this helps diagnose tyre wear and steering complaints.


Given Data / Assumptions:

  • Conventional passenger car with Ackermann-type steering linkage.
  • Low-speed cornering where slip angles are small.
  • No four-wheel steering or advanced torque vectoring.


Concept / Approach:
For pure rolling about an instantaneous center on the extended rear axle line, the inside wheel must steer at a larger angle than the outside. This creates a toe-out-on-turns condition when viewed relative to each other during cornering. The linkage achieves this by geometry of the steering arms and track rod lengths.


Step-by-Step Solution:
Identify the instantaneous center of rotation for the vehicle path.Require both front wheel axes to intersect that center to avoid lateral scrub.Conclude that the inner wheel must adopt a larger steering angle, producing toe-out on turns.


Verification / Alternative check:
Workshop alignment specifications include a check called toe-out on turns, measured with turntables, confirming the unequal angle relationship dictated by geometry.


Why Other Options Are Wrong:
Options a, b, and c are each correct; therefore the most complete answer is all of the above.


Common Pitfalls:
Confusing static toe (straight-ahead alignment) with dynamic toe during a turn; assuming both wheels turn by the same angle in simple linkages.


Final Answer:
all of the above

More Questions from Automobile Engineering

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion