Crank set for cycle with 40 teeth, Suitable for all type of cycles. Cotterless crankset for single, 7 gears, 21 gears. Convert 3 gears in single gear using this Crank set. Double side protection. Cotterless Crankset for cycles, perfect replacement for 3 gears crankset., comes with double side protection, contain 40 teeth with 2 side protection ,no more gear problems. The crankset is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chain wheels attached to the cranks, arms, or crankarms to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain.