....And a bicycle with steering geared so handlebars turned left gives front wheel turned right and vice versa is unridable.
Bicycles are actually turned by 'counter steering'. To turn left, you move the bars to the right. The bicycle intially steers right, then drops over into a banked turn to the left. Cylists (including me) are genrally not aware of this, and don't really know how they turn - they just 'do it'.
Motorcyclists are very aware of it, because with the much heavier and faster-turning wheel of a motorcycle this gyroscopic effect is very obvious, to the extent that to make a motorcycle deliberatley 'turn in' quickly, the rider deliberately counter-steers; pull on the left handlebar or push on the right handlebar, and the bike immediately drops into a controlled right turn.
This effect obviously doesn't happen at very slow speeds where the gyroscopic effects of the spinning wheel are too weak. I call this sort of turn 'yaw mode'. It is used when wheeling the bike in and out of the garage, or when riding at very low speeds, such as 'U' turns in the width of the road etc.
SSD