Jackknifing and Trailer Swing SS17036AE (7 Min.)
Jackknifing is the simple but too often hazardous result of a chain of events that occur when the driver locks up the drive axle brakes on the tractor. If you lock up the steering axle brakes, the truck will move straight ahead regardless of the wheel angle. If you lock up the trailer axle brakes the law of physics takes over, and you’ll experience the trailer swing, a kind of reverse jackknifing where the trailer moves around the tractor, pivoting on the fifth wheel or breaking away from the fifth wheel completely. This video takes a look at what jackknifing can cause and what drivers can do to prevent it.