Identification of key parameter influence on efficiency of chain drive for track cycling − Preliminary results

The presented paper investigates the efficiency of chain drive transmissions in track cycling, where performance optimization is critical as a win or loss between athletes is often decided in a matter of 1/100 seconds. A 2D quasi-static model (Chain Drive Efficiency Model, CDEM) was previously developed. It includes first a simulation of the global kinematics and then uses the roller movement along tooth profiles as well as the relative movement of chains part to calculate the efficiency. A dedicated experimental test rig was also designed to reproduce the chain transmission track cycling conditions. The test rig features two instrumented shafts with torque transducers, enabling efficiency measurements under distinct loading conditions representative of endurance and sprint races. Results from both the model and test rig confirm the significant influence of chain tension and sprocket tooth number on efficiency, while misalignment showed negligible effects. Lubrication tests revealed that solid wax-based lubricants provide notable performance improvements. At the contact scale, the study compared industrial tooth profiles to newly proposed cycling-specific profiles. The CDEM predictions, consistent with experimental data, identified meshing losses as the primary source of dissipation, while roller-related losses were negligible. These findings provide insights for optimizing track cycling chain transmissions and highlight the potential of localized improvements, including lubricant choice and tooth profile design.