Development of a servohydraulic roller test bench for indoor evaluation of the vibrational comfort of bicycle components

One of the most important parameters evaluated by racing and trekking cyclists is vibrational comfort: as generally accepted, it is closely correlated to the response of bicycle components in combination with the cyclist's characteristics. Vibration transmissibility of wheels and saddles was recently studied during lab tests using a wooden dummy bottom resting on the saddle or in road tests on an instrumented racing bicycle at different speeds on different surfaces. The use of shakers is also well established in the evaluation of cyclist's posture effects on the overall bicycle behaviour. In fact, in previous works, either a servohydraulic actuator was applied to the seatpost of a bicycle frame hinged at the front wheel axle with a cycling tester, or two electrodynamic shakers were applied under the wheels of a fully equipped bicycle, with a cyclist sitting statically on the saddle. In the present study, the combination of a servohydraulic actuator and a roller type bench allowed to overcome the limitations of the former experiences. Random vibrations were input to the bicycle-cyclist complex by means of rollers supporting the rear wheel while cyclists were cycling unrestrained on the rollers. The test bench setup and tuning approach are presented for comparison with results available from previous bench and road tests.