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What is the difference between a tractor jackknife and a trailer jackknife?
- A.A tractor jackknife only happens in reverse, while a trailer jackknife only happens going forward
- B.A trailer jackknife involves the steering tires, while a tractor jackknife involves only the fifth wheel
- C.There is no real difference; the two terms describe the same wheel locking
- D.In a tractor jackknife the drive wheels lock and the tractor spins around toward the trailer; in a trailer jackknife the trailer wheels lock and the trailer swings around toward the tractor
Correct answer
D. In a tractor jackknife the drive wheels lock and the tractor spins around toward the trailer; in a trailer jackknife the trailer wheels lock and the trailer swings around toward the tractor
Why
The name tells you which unit lost traction first. Locked drive wheels let the tractor rotate, while locked trailer wheels let the trailer swing, and the recovery and prevention emphasis differ for each case.
Manual topic: Combination Vehicles - Skids and Jackknifing · From the Combination Vehicles practice bank (CV-129).