Explain the difference between throttle-induced instability and brake-induced instability, and how to differentiate between them on track.

• A. Throttle instability is random wobble; brake instability is nose dive.
• B. Throttle instability shows when applying throttle (rear step); brake instability shows during braking (nose dive); respond by smoothing inputs in respective phase.
• C. They are the same phenomenon.
• D. Only braking causes instability.

Answer: (B)

The difference lies in when the car becomes unsettled and what that reveals about load and traction. Throttle-induced instability shows up as you apply power: the rear tires can break traction and the car steps sideways or yaws as grip is regained, often described as a rear step. Brake-induced instability shows up during braking: the front end dives and the weight shifts forward, and if braking is too abrupt or deep, the rear can lose grip and the car can feel unsettled.

To tell them apart on track, observe when the unsettling motion starts. If it begins as you roll on the throttle, you’re seeing throttle-induced instability; if it begins during braking, it’s brake-induced instability. The remedy is to smooth the inputs in that phase: ease into throttle and modulate power to keep rear grip, or brake more gradually and progressively to maintain front-end grip and stability.