The stem (technically called a "handlebar stem" or, more slang-wise, a "pipe") is the component connecting the fork to the handlebar. The stem length ranges from 70mm to 130mm. The longer it is, the more "recumbent" our riding position, improving aerodynamics and shifting the center of gravity forward, which significantly impacts efficiency while climbing. There are two types of stems based on their mounting method. The stem that "sinks" into the steerer tube (the older type), sometimes called a pipe, is dominant on less expensive bikes, but is also the basic model used on modern folding bikes, such as fixed gear bikes and single-speed bikes. Steerer tube (fork) diameters vary – 21.1mm, 22.2mm, 25.4mm, and sometimes 28.6mm. This type of stem inserts into the center of the fork tube and is stabilized by a spacer cone. The handlebar itself is mounted with a clamp stabilized by one or two screws (this allows you to change the handlebar angle, which also affects your riding position). The stem mounted on the fork tube ("steerer tube") is an Ahead stem. Due to the different steerer tube diameters, stems with the following inner clamp diameters are available: 1", 1 1/8", 1 1/4", and 1.5". When choosing a stem, you should also consider the handlebar diameter. There are three standards: 25.4", 26", and the so-called "oversize" (31.8mm). In summary, the longer the stem and the smaller the angle, the more inclined your stance will be. Both of these values are chosen according to your preferences and needs. For sporty bikes, we recommend using a nearly flat stem (+/- 6 degrees – remember that the stem can be rotated to change its rake) and longer stems (90-130mm).
