Two Tiny Wheels Keep New Bicycle Upright, 1934

In 1934, a four-wheeled bicycle which made its appearance in Germany could be mounted easily, even by a beginner, and could be parked anywhere.

Two small auxiliary wheels were attached by movable brackets to the frame of the cycle and were raised or lowered by moving a lever on the handle bar. So long as these wheels remain lowered, the cycle stands upright as shown below. When in motion, they were raised.