Skid Control
What causes a skid
A skid is loss of traction. In combinations, overbraking, too much speed for the curve, and abrupt steering are the usual causes. The exam asks you to identify the type of skid and the recovery.
Types and recovery
- Rear-wheel skid: the drive or trailer tires lose grip and the back of the vehicle slides out. Release the brakes to let the wheels roll, look where you want to go, and steer in the direction of the skid (the direction the rear is sliding). Do not keep braking.
- Front-wheel skid: the steering axle loses grip and the vehicle keeps going straight. Release the brakes and steer; steering returns only when the tires regain traction.
- Braking skid: wheels are locked. Release and reapply with controlled braking, or use stab braking if there is no ABS.
- Acceleration skid: back off the throttle smoothly.
Worked example
You brake on wet pavement and the trailer swings left while the drive axles are locked. The rear of the combination is sliding left. Release the brake pedal, steer left to follow the trailer, and straighten as traction returns. Braking harder would deepen the jackknife.
Traps
Steering away from the skid; staying on the brake because the pedal feels right; using engine brakes on ice; overcorrecting and starting a second skid in the other direction. If the tractor has ABS, keep steady pressure and steer-do not pump.