Handlebars will only be correctly positioned when they create a certain pretension in the back muscles. The back muscles and stomach muscles need to be tensed slightly so that they will be able to stabilize the spine and protect it from excessive stress. If the muscles are passive, they cannot fulfill this important function.
Determining the inclination of the torso! The inclination of the torso depends on a person's individual riding style. Someone who wants to ride fast will prefer a flatter inclination, while recreational and city bikers favor a more upright posture.
Choose a handlebar height that matches the inclination you want.
If the handlebar has to be raised significantly a shaft must always be chosen with the appropriate length ( classic stem: observe the minimum insertion depth / ahead stem: use an adapter).
Note: If you adjust the handlebar height using an adjustable stem angle (c), then the handlebar height (a) and stem projection (b) change at the same time! This also changes the angle of the upper arm to the upper body.
Each position is characterized by a different upper-arm-to-torso angle. This determines how much supporting work the shoulders, arms and hands must do. The upper-arm-to-torso angle is set by adjusting the length and angle of the stem. If your bike has a stem that allows the angle to be adjusted, then you can fine-tune the upper-arm-to-torso angle most precisely.
Classic (Dutch) bike position: The angle is a very small one, the upper arms run almost parallel to the torso and the hands sit loosely on the handlebars (no supporting work).
City bike position: An angle of 90° is a good guide. But many people prefer a smaller angle, down to around 60°, because this means less supporting work for the shoulders, arms and hands.
Trekking bike position: The optimal angle is around 90°. The load is then very well distributed.
Sporty position: The angle is over 90°. This produces a flatter, more aerodynamic posture. The shoulders, arms and hands have to do a lot of supporting work. The pressure in the seat area shifts forward.
Caution: setting the handlebars could alter the position of the pelvis on the saddle. This can have a major effect on the position of the hip joint and shorten the useful leg length at the saddle by up to 3 cm.
Important: after setting the handlebars, the saddle height and position should be rechecked. A subsequent re-adjustment of the saddle may be necessary.
