In the nascent days of two-wheeled, self-propelled locomotion, early velocipedes like the boneshakers had their forks positioned vertically. At a walking pace, or maybe slightly faster which was about as fast as a boneshaker could travel, the upright fork worked passably well. Unfortunately, any time the pace picked up, or the front wheel was deflected by an obstacle, the front wheel exhibited what we now call caster flutter, or shimmy, which is an uncontrolled oscillation around the wheel’s vertical axis. Many of us have experienced a mild form of this, usually when decelerating from about 55 to 40 miles an hour with a light grip on the bars, and it’s unnerving. Imagine how much fun it was when the fork might rotate 180 degrees, with the predicable unpleasant outcome. This nasty turn of events could even be initiated if the rider’s attention lapsed and he relaxed his grip on the bars at the wrong time, which as you might imagine, often made riding an early two-wheeler way more exciting than it had to be.