Speed wobbles occur when the board begins to involuntarily oscillate in short mini “S” turns, giving the rider a feeling of loss of control.
This typically happens when too much weight is placed on your back leg. While speed wobbles usually occur at higher speeds, you can also wobble at low speeds by distributing your weight in the wrong way. Remember to keep your back truck tighter than the front to avoid too much steering input from the rear.
The most important thing is to stay calm and try to relax because tense leg muscles can exacerbate the problem.
Try carving in one direction, as consciously turning will often stabilize the board and stop the wobble. Lean over your front foot and slowly let off the throttle until the speed wobble stops. Tightening the kingpin on your trucks may also help to reduce speed wobbles. Just be sure not to over tighten so you can still freely turn. Try only adjusting a quarter turn at a time.
Over time, frequent riding will strengthen the stabilizing muscles in your ankles and legs, eliminating the frequency and severity of speed wobbles.