The crankset, or chainset, 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, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chainwheels attached to the cranks or arms to which the pedals attach. MTB chainsets comprise of one, two or three chainrings. Bicycle cranks can vary in length to accommodate different sized riders. Major manufacturers typically offer crank lengths for adult riders from 165 mm to 180 mm long in 2.5 mm increments. It would seem evident that riders with shorter legs should use proportionally shorter cranks, while those with longer legs should use proportionally longer cranks. However, the exact length an individual cyclist feels most comfortable with may differ depending on the type of cycling they take part in. Most riders tend to go for shorter cranks for fast cadence cycling such as criterium and track racing however some riders prefer longer cranks for lower cadence cycling such as time trialling and mountain biking, where leverage is a important.