The stem ( stem) is the body that transmits the force from the steering tube to door handle bars or, if integrated, directly to the steerer tube of the fork.
The stem is a fundamental element of some types of steering of the bike; to be precise, the stem is typical of stems consisting of two or three pieces: the top tube of the handlebars, the stem and, in the event, even the door handle bars.
Sometimes, the stem is integrated into the door handlebars and, especially the older ones, constitutes a single piece with the handlebars.
The stem is designed to lock the handlebar tube and possibly even the door handle bars; This feature includes two types: one for the handlebar tube and one for the door handle bars.
Measurement and Regulation
The stem can, depending on length and angle, change the chassis of the bike up to specialize use in various disciplines.
This happens especially in mountain biking in which, by virtue of many uses, height, length and angle of the handlebar affect load balancing and the rider’s posture in a radical way.
By changing the length of the stem you can adjust the speed of the steering. In practice, reducing this dimension of stem you can increase the suddenness of the reverse clutch and vice versa; Obviously, the choice of this measure depends mainly on the size of the vehicle and driving technique.
There is also a version described as a “compromise” between the directional characteristic of short stem speed and comfort while pedaling a long stem; This is the case of the stem short with wide handlebar tube.
Another feature that is costly to the bike riding is the angle between the tightening of door handlebars and handlebar tube (compared to an ideal plan), so much so that some companies have opted to create specially adjustable stem.
For traditional ones, better not forget that that parameter is added (or subordinates) steering angle (of the steerer tube); with the incline increases proportionally too handlebar height from the ground and, therefore, decreases the load on the front end.
There are several types of stem, which differ in:
- Length and angle (or presence)
- Clamping type
- Dimensions of the accommodation
- Brand and price.
The price of stems (separate and independent) varies especially according to material, brand and the presence or absence of regulation. A stem of low range costs an average of about 5 €, whereas a high gamma easily reaches 350 €.