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

Sprockets are used in bicycles, motorcycles, cars, 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. Probably the most common form of sprocket may be within the bicycle, in which the pedal shaft carries a huge sprocket-wheel, which drives a chain, which, subsequently, drives a small sprocket on the axle of the trunk wheel. Early automobiles had been also largely driven by sprocket and chain system, a practice mainly copied from bicycles.

Sprockets are of various designs, no more than efficiency being claimed for every by the originator. Sprockets typically do not have a flange. Some sprockets used in mixture with timing belts have flanges to keep the timing belt centered. Sprockets and chains are also used for power chain sprocket transmission from one shaft to some other where slippage is not admissible, sprocket chains becoming used rather than belts or ropes and sprocket-wheels instead of pulleys. They could be operate at high speed and some kinds of chain are so constructed concerning be noiseless even at high speed.