Читать книгу The Bonsai Handbook - Adam Dickson - Страница 26

The measurement that most influences your upper-body position is the combination of handlebar extension and top-tube length, or the so-called ‘reach’. In a standard off-the-shelf frame the length of the top tube is correctly related to the length of the seat tube and correlates to the upper body measurements of a cyclist of average size who would need that frame size.

To determine a proper stem extension, place your hands in the drop position (or on the tops of the brake levers) while you are comfortably seated in your saddle with your elbows slightly bent (ground must be level!). In this position the front wheel’s hub should then be obscured by the middle section of your handlebar. If proper top tube/stem length combination cannot be achieved with a 105-135 millimetres (4.1-5.3 inches) stem, try a larger frame.

It is clear that a correct aerodynamic position and a comfortable position of the torso do not always go hand in hand. Depending on your anatomy, flexibility and the discipline you engage in, the reach could be longer for better aerodynamics and higher speeds, or it may need to be shorter for back or neck comfort and improved efficiency uphill. If your reach to the handlebar is wrong, use stem length to correct it, not fore/aft saddle position.