Engineering Evaluation of “Reactivity” of Racing Bicycle Wheels

During road cycling the cyclists can evaluate the behavior of a wheelset in terms of several performance requirements: among all, the wheels reactivity, defined as the wheels quickness in transforming cyclist actions into bicycle acceleration, resulted to be one of the main performance requirements perceived by the cyclists. Together with the subjective evaluation test sessions, a set of engineering indexes, representing the most representative technical measurements of the cyclists perceived performance requirements, is also needed for an effective product innovation approach. Aim of the present work was the development of a method for the computation of a wheel reactivity engineering index. The method is based on the computation of the energy absorbed by the wheel during a sprint action performed by the cyclist. Each energy contribution to the total energy absorbed by the wheel was quantified; the parameters considered for the index computation were obtained by the analysis of data collected in the field tests of an instrumented bicycle. The high correlation coefficient obtained between the engineering reactivity index calculated for three different wheels and the perceived reactivity evaluated by the cyclists, regarding the same wheels, was considered as a validation of the developed method.