- Mar 16, 2009
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In a discovery that could lead to better and safer bicycle design, researchers have shown that long-accepted "gyro" and "caster" effects are not needed to make a bike balance itself. In fact, it's a mixture of complicated physical effects – linked to the distribution of mass – that makes it so a bicycle can remain up when moving.
TMS Bicycle
stable without gyros or trail
(TMS = two-mass-skate)
Long known, but still amazing, is that a moving bicycle can balance itself (see videos). Most people think this balance follows from a gyroscopic effect. That's what Felix Klein (of the Klein bottle), Arnold Sommerfeld (nominated for the Nobel prize 81 times) and Fritz Noether (Emmy's brother) thought [1]. On the other hand a famous paper by David Jones [2] (published twice in Physics Today) claims bicycle stability is also because of something called "trail". Trail is the distance the front wheel trails behind the steer axis. The front wheel of a shopping cart castor trails behind its support bearing and so must a bicycle front wheel, Jones reasoned. Jones insisted that trail was a necessary part of bicycle stability.
TMS Bicycle
stable without gyros or trail
(TMS = two-mass-skate)
Long known, but still amazing, is that a moving bicycle can balance itself (see videos). Most people think this balance follows from a gyroscopic effect. That's what Felix Klein (of the Klein bottle), Arnold Sommerfeld (nominated for the Nobel prize 81 times) and Fritz Noether (Emmy's brother) thought [1]. On the other hand a famous paper by David Jones [2] (published twice in Physics Today) claims bicycle stability is also because of something called "trail". Trail is the distance the front wheel trails behind the steer axis. The front wheel of a shopping cart castor trails behind its support bearing and so must a bicycle front wheel, Jones reasoned. Jones insisted that trail was a necessary part of bicycle stability.