A sprocket[1] or sprocket-wheel[2] is a profiled wheel with the teeth, or cogs,[3][4] that mesh with a chain, monitor or other perforated or indented materials.[5][6] The name ‘sprocket’ applies generally to any wheel upon which radial projections engage a chain passing over it. It is distinguished from a gear in that sprockets should never be meshed together directly, and differs from a pulley for the chain sprocket reason that sprockets have tooth and pulleys are easy.

Sprockets are used in bicycles, motorcycles, vehicles, tracked vehicles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or even to impart linear movement to a track, tape etc. Maybe the most common form of sprocket could be found in the bicycle, where the pedal shaft bears a big sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the rear wheel. Early automobiles were also largely powered by sprocket and chain mechanism, a practice mainly copied from bicycles.

Sprockets are of various designs, no more than efficiency becoming claimed for each by its originator. Sprockets typically don’t have a flange. Some sprockets used in mixture with timing belts possess flanges to keep carefully the timing belt centered. Sprockets and chains are also used for power transmission in one shaft to some other where slippage isn’t admissible, sprocket chains getting used instead of belts or ropes and sprocket-wheels instead of pulleys. They may be operate at high speed and some kinds of chain are so built as to be noiseless also at high speed.