I ride a 12" wheeled PedalFlow, matching peoples walking speeds (SLOW!!!), and I experience no wobbles. I also don't really experience any issues with my 20" wheeled folders, while riding fast OR slow. I find twitchiness & wobbling to be something I don"t experience. Maybe I'm just used to riding folders? Even when I had a Dahon Curve for a short time, I had no problem riding it. It felt amazingly solid, and I was quite impressed at how the ride was more like a larger wheeled bike.

Like I said, I'm probably used to riding folders,...I really don't notice issues.