That's not what stability is. A stable bike is one in which the steering is stable and easily controlled at various speeds. It's a function of steering geometry and mechanical trail. And the Strida is among the very most unstable folders on the market.

Answer honestly. Would you ride the Strida downhill at a 30 degree incline with a serious curve at the bottom without using the brakes, like you would a mountain bike? How about at over 15 miles an hour [like a racing bike]? A good folder should be able to do both easily.