The stem is a piece of bike frame which attaches the handlebar to the bike and is important when relating the bike to the user’s body proportions. It means that the stem is important when fitting the bike into its muscular proportions since it affects the reach to the handlebars and the handling characteristics of the bike. Stems that are longer increase the time taken to manipulate a bike’s controls and therefore improve its handling at high speeds, whereas short stems make a bike easier to maneuver which is good for mountain biking. Also the angle of the stem and its length can be changed in order to obtain a comfortable and efficient position for riding.