When you are riding a bicycle or a motorcycle and are about to make a turn, you (often subconsciously) perform a small “countersteer” in the opposite direction of your turn before actually turning in your desired direction. That is, if you are about to make a right turn on your bike, you actually make a slight left turn first before actually turning right.

First of all, one must understand that a bicycle is actually an “inverted pendulum” (think of a pendulum, such as one in a clock, except upside-down). In other words, a bicycle will surely fall to one side if it is not balanced. We know this from everyday experience.

So, why is countersteering necessary? The concepts lie in basic mechanics. When riding a bike, turning the front wheel in one direction causes the bike to lean in the opposite direction due to a centripetal force. Therefore, the initial countersteering will cause the bike to lean into the direction of the desired turn. This lean is necessary because when executing the actual turn, there is a centripetal force that acts outward on the bike, and the force of gravity acting on the inward-leaning bike will cancel the outward centripetal force to keep the bike upright during the turn. If there is no inward lean during a turn, then the outward centripetal force will knock the bike over and cause it to fall down to the ground, resulting in a poor cycling experience for both the rider and the bicycle.

Despite being a necessity, countersteering isn’t something that is explicitly taught to a beginning bicyclist. It is something natural that is picked up when one attempts a turn on a bicycle for the first time. This makes countersteering an interesting and subtle phenomenon in bicycle dynamics.

Countersteering is important in bicycle dynamics.

Categories: In-Depth Articles, Science
Tags: Bicycles, Countersteering, Dynamics, Mechanics
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