The most likely reason for speed wobbles in anyone starting out, or only going a speed a street skater could posibly go- is incorrect weight distribution, or overcorrection.
As someone starting out you should think of the front of the board as the steering of your board, the back foot is basicly only supporting the weight of your leg as a starter. If you have good weight distribution and don't try to fight road feedback, you will have a hard time wobbling below ~30 on any setup rkp, at any skill level.
Some body positioning things to keep in mind:
Looking down the hill, and thinking about where you are heading.
Leaning forward when you get scared and not backwards, its a bad habit to go "away from the danger" by leaning back, this will cause you to fall.
Basing your stance on your board off of the front foot being over or close to over the front truck.
Making sure your front leg is strong enough to support all your weight for the length of your ride.
Having your hips and shoulders square forward with the hill, NOT like street skating, surfing, snowboarding.
Some gear checks to run through for wobs:
Make sure your board doesn't have any flex.
Ensure your front truck is at higher or the same degree than the rear.
Check your bushings are not cones or similar, and not old, and the front is looser or equal to the rear.
Make sure kingpin nut isn't cranked down to make the trucks tigher, and bushings duro are the only source of tightness.
