A _____ will occur when the drive wheels attempt to take over the front wheels, causing the rear of the tractor to swing out.

A _____ will occur when the drive wheels attempt to take over the front wheels, causing the rear of the tractor to swing out.

• A. trailer jackknife
• B. tractor jackknife
• C. front wheel skid
• D. all-wheel skid

Answer: (B)

A tractor jackknife occurs when the drive wheels lose traction and pull the rear of the tractor around toward the front, creating a sharp angle between the tractor and the trailer. In this situation the front wheels may seem to hold or steer straight, while the powered rear wheels push the tractor’s rear outward, causing the whole rig to fold like a jackknife. This is distinct from a trailer jackknife, where the trailer itself swings toward the cab, or from wheel skids that don’t involve the tractor and trailer pivoting relative to each other.

A tractor jackknife occurs when the drive wheels lose traction and pull the rear of the tractor around toward the front, creating a sharp angle between the tractor and the trailer. In this situation the front wheels may seem to hold or steer straight, while the powered rear wheels push the tractor’s rear outward, causing the whole rig to fold like a jackknife. This is distinct from a trailer jackknife, where the trailer itself swings toward the cab, or from wheel skids that don’t involve the tractor and trailer pivoting relative to each other.