It is difficult to single out the more or less significant components of a bicycle. But the bicycle chain is one of the most important elements that participates directly in the movement, transferring the torque of the main sprocket to the driven one. Therefore, you need to choose a bicycle chain taking into account many factors: the type of bike, riding style, the weight of the cyclist. Among the popular manufacturers of bicycle chains (Shimano, KMC, Sunrace, Sram) there is a division by class and by the number of cassette stars, which greatly simplifies the choice. Bicycle chains of different qualities lend themselves to stretching and deformation in different ways, which is due to different metal alloys, the design of the links themselves and connecting pins. Chains of different brands are interchangeable with each other, provided that the number of stars on the cassette matches. For cassettes 7-8 stars and cassettes 9 stars or 10 stars, the chains will differ in the width of the links and simply will not fit between the stars. Separate from all are chains for single-speed bicycles (singl speed). Therefore, the bike chain is matched to the cassette.