Lightweight design is fundamental to the efficiency and functionality of a bike. Likewise, the efficiency and functionality of a bike are fundamental to a child's success when learning to ride.
Before we get into the difference between bushings and bearings it is important to note that the “headset” is the name given to the bearings or bushings that fit into the head-tube (where the fork and handlebars meet the frame) of the bicycle. The headset bearings support the weight of the rider while allowing for steering rotation.
Typically found on adult bikes a bearing is designed to “bear” more weight. Since bearings are designed to carry more weight they have multiple parts to them such as a threaded fork tube, steel ball bearings, steel bearing cups, steel cone nuts, steel lock nut, and steel washers. While this heavy-duty assembly might be necessary to support a full-grown adult, it is simply excess weight and complexity when there is no need for it to support the weight of a toddler.
By contrast bushings are designed as a single part. The Strider bushing headset provides astounding weight reduction, weighing in at around 23 grams (0.8 oz, only 1/20'th of a pound!), while the typical bearing headset found on the pedal bike weighs 130-205 gr (a full 1/4 - 1/3 of a pound). An average Strider rider weighs just 13kg (29 pounds), which makes utilizing lightweight components fundamental to the overall bike design. The headset bushing on a Strider uses durable, injection molded, polypropylene bushings and washers top and bottom to support the rider’s weight while still maintaining smooth steering action.