Which of the following is NOT a standard part of the steering system?

The choice identified as the correct answer, which states that brake rotors are not a standard part of the steering system, is accurate because brake rotors are solely part of the braking system. The steering system primarily comprises components that function to control the direction of the vehicle.

The steering column, for instance, connects the steering wheel to the steering mechanism and transmits the driver's input. The gear box, often referred to as the steering gear, converts the rotational motion of the steering wheel into the linear motion required to move the vehicle's wheels. The steering knuckle serves as a pivotal connection that allows the wheels to turn while being connected to the suspension systems, making it an essential element in the steering system.

Therefore, understanding that brake rotors are exclusively involved in the braking process helps clarify why they do not belong to the steering system.