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Difficulty: MediumSkidding Causes and Prevention

Downshifting abruptly into a low gear at speed on a slippery road surface can cause the drive wheels to lose grip and initiate a skid.

Answer: Answer

Answer

True. Abrupt downshifting introduces sudden engine braking torque to the drive wheels, which can exceed the reduced tyre grip available on a slippery surface and trigger a skid.
The statement is true because abrupt downshifts produce sudden engine braking forces at the drive wheels. When road friction is low, this torque discrepancy can break tyre adhesion and initiate a skid.

Step-by-Step Solution

1
Analyse the mechanical effect of sudden downshifting at road speed
Identified that shifting into a low gear creates immediate drivetrain drag (engine braking) on the drive axle
Understanding how vehicle speed interacts with engine gear ratios
2
Evaluate the friction forces at the tyre-road contact patch on slippery surfaces
Determined that available tyre adhesion is significantly reduced on wet, icy, or contaminated roads
Assessing the traction limit before loss of control occurs
3
Synthesise the interaction between engine braking torque and reduced road friction
Concluded that the abrupt retarding force can overwhelm tyre grip and initiate a skid without the brake pedal being pressed
Direct application of skid causation principles

Key Concept

Drivetrain-induced skidding caused by abrupt engine braking on low-friction surfaces
Estimated Time:45s
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Topics

Skidding Causes and Prevention

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