If we take a simplified look at the issue of the correct seating position on the bike, the problem can be reduced to exactly three points of contact with the bike: Pedals, saddle, handlebars. And the coordinates of these three contact points, the magic triangle so to speak, determine the riding position: if you move the positions of the three corners A-B-C, the position changes from stretched and long to short and upright.
One distance is predetermined by the anatomy of the human body and the basis of the necessary sitting position: the legs, our drive motor when pedalling, only work optimally at certain angles due to the design features of our skeleton and musculature: ankles, knees and pelvis and the associated musculature with quadriceps and calf muscles have developed into stabilisation and walking tools during evolution and do not function like a piston engine.
In order to avoid damage to the joints and tendon apparatus, especially the often sensitive kneecap with tendon (tibialis), each person needs a certain saddle height according to their leg length, i.e. an optimum distance from saddle to pedal.
The decisive factor is distance 1: The seat height, determined by your own leg length, in order to be able to optimise your leg power. This results in a specific frame height (2). The resulting frame geometry determines the seat length (3), which can be varied by moving the saddle and using different stems. The saddle position, distance from saddle nose to pedal (4), is also determined by your body measurements, as the perpendicular of the kneecap should not be in front of the pedal axle. The cant (5), i.e. how far the handlebars are above the saddle, can be varied using spacers or steeper stems.
The full-length article from issue 1/2006 is available as a free PDF download.
