What infamous, high-risk failure mode was common to the high-wheeler design?
The header.
The most significant and dangerous inherent flaw in the penny-farthing design was known as the 'header.' This incident occurred because the rider's entire mass was positioned precariously high up and far forward, directly over the center of gravity, which was situated above the massive front axle. Any sudden, unplanned deceleration—such as hitting an unexpected bump, encountering a severe dip in the road, or braking too abruptly—would instantly cause the entire machine to pitch forward. The rider would be violently thrown headfirst over the handlebars and onto the ground, leading to frequent and often fatal head injuries. Riders even developed counter-measures, such as putting their legs over the handlebars when going downhill, in a desperate attempt to ensure they were thrown off feet-first rather than headfirst.
