Development of a Test Method for the Comparative Analysis of Bicycle Saddle Vibration Transmissibility

Vibrational comfort is one of the most important parameters evaluated by cyclists during bicycle riding. A method for measuring the saddle vibration transmissibility was developed with the aim of comparing the comfort properties of bicycle saddles without any influence of the full bicycle frame, using a quantitative approach. Three different bicycle saddles were mounted on a stiff seatpost clamped to the extremity of a vertical servohydraulic cylinder: saddles were loaded by a UNI 10814 standard wooden dummy bottom carrying deadweights. After applying a sinusoidal sweep of 0.6 mm amplitude to the cylinder, from 1 to 100 Hz, with steps of 2.5 Hz, the application of two piezoelectric accelerometers allowed evaluating the magnitude of the transfer function H between the input acceleration at the cylinder shaft and the output acceleration at the dummy, in the range 1-100 Hz. The three curves of the transfer function magnitude were compared and analyzed in order to introduce a Vibrational Comfort Index and to rank the tested saddles from the engineering quantitative point of view.