![]() ![]() The Draisine or velocipede was invented in the early 19th century Print Collector / Getty Arend Schwab, one of the report’s co-author’s and a biomechanical engineer at Delft University of Technology in the Netherlands, “they look almost identical to the ones made around 1890, when scientists first looked at the self-stability of the bike.” “If you look at the bicycles of today,” says Prof. And don’t forget wheelbase length, which helps keep your bike stable at speed. You may have noticed that it’s much easier to ride a bike no-handed when it has a long stem fitted - that’s because the weight of the handlebars is further ahead of the front wheel. In addition to gyroscopic forces and fork trail, there’s also centre of mass, which is one of the key areas highlighted by Papadopoulos and colleagues. It’s an exciting area of bike design theory, and incredible to think that despite the safety bicycle emerging in the late 19th century, the exact relationship between these forces still isn’t known for certain. ![]() This is where it gets complicated, as there’s no common agreement on the exact relation of the different factors that help keep a bike upright when in motion. What else might be helping your bike stay upright when in motion? The team’s efforts culminated in two papers, the more theoretical Linearised Dynamics Equations For The Balance And Steering Of A Bicycle: A Benchmark (2007), and the more practical and mind-blowing A Bicycle Can Be Self-Stable Without Gyroscopic or Castor Effects (2011). And in the later study by David Jones, the team says that his calculations were based on a bicycle being stationary, rather than moving. In the earlier study from 1910, the team says that there were sign errors that - when corrected - lessen the importance of gyroscopic forces. However, Papadopoulos and his team say that there are errors in both studies mentioned above (1910’s Über die Theorie des Kreisels on gyroscopic effect on bikes’ self-stability by Felix Klein, Fritz Noether and Arnold Sommerfeld and 1970’s The Stability of the Bicycle on the castor effect by David Jones). In 1970, the British chemist and writer David Jones built a bike with no gyroscopic effect, and he concluded that the self-stability of a bike is due to fork trail. The interesting thing in relation to bikes, which only have two contact points with the ground, is that this means the front wheel automatically goes into a turn when a moving bike leans - it is self-correcting. It is as if the axis were towing the wheel in its movement. This happens because the contact point to the ground of the wheel is behind the contact point to the ground of the steering axis, a distance also known as “trail” (labelled ‘C’ in the illustration above). If you move the cart in any direction, the castor (comprising a steering axis and a wheel) will always follow the cart, like a dog on a leash. In 1970, the British chemist and writer David Jones built a bike with no gyroscopic effect, and he concluded that the self-stability of a bike is due to fork trailįork trail, on the other hand, is something we can witness on grocery carts. ![]()
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