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How does total vehicle weight affect brake heating on a long grade?
- A.Weight does not affect heating if the load is centered
- B.A heavier vehicle has more energy for gravity and the brakes to manage, so it will heat brakes faster at the same speed and grade
- C.Heavier vehicles cool their brakes faster
- D.Weight only matters when climbing, not descending
Correct answer
B. A heavier vehicle has more energy for gravity and the brakes to manage, so it will heat brakes faster at the same speed and grade
Why
Gravity pulls the full mass down the grade continuously, and any energy the engine brake cannot absorb becomes heat at the drums. Heavy loads therefore demand lower gears and lower speeds, not simply more pedal pressure.
Manual topic: Air Brakes - Brake Fade and Heat · From the Air Brakes practice bank (AB-192).