Trundle wheel

The trundle wheel is a measuring device, a simplified form of a surveyor's wheel. It is commonly used by people who need an easy way to find the rough distance from one place to another. The trundle wheel is composed of a wheel, a handle which is attached to the axle allowing the trundle wheel to be held easily, and a clicking device which is triggered once per revolution of the wheel. Trundle wheels are not as accurate as other methods of measuring distance but are a good way to get a rough estimation of a fairly long distance over a good surface.

It works by having a wheel which has a circumference of exactly 1 metre (or other known unit of measure), hence one revolution of the wheel equates to 1 unit of distance traveled on the ground if there is no slip. Every time the wheel makes a rotation, the wheel produces an audible click which is then counted and therefore the number of clicks that are counted by the user is approximately the number of distance units traveled. Due to the design of the trundle wheel, it has the potential to not always travel in a straight line which may add extra distance to the final reading.