Eloy Vázquez Fernández successfully defended his MSc thesis titled Vibration Impact on Cycling Performance: Understanding power loss due to vibration and the parameters that influence it on July 17, 2025.

Eloy devised a set of experiments to mimic the vibration experienced cycling over cobblestones from 10 to 30 km/h and carefully measured the power loss caused by the vibrations. He tested two postures (seated normally and up off the saddle), three muscle contraction states (normal, relaxed, and stiff), and a range of tire pressures (3.5 to 5.5 bar). He showed that vibrational losses can equal or exceed aerodynamic losses on a rough surface like cobblestones. Lowering the tire pressure or rising from the saddle can save about 200 watts at 30 km/h. He proposed a quadratic model to relate speed and vibrational power loss which is a departure from the classic rolling resistance models that are linear in the speed. Overall vibration power losses can contribute up to 60% of the total power loss traversing cobblestones, showing vibration power loss needs more attention than it has historically received. Eloy also calls into question the use of the International Roughness Index (IRI) for classifying road roughness for these purposes because it neglects the variation of vibration across frequencies.

Power loss due to vibration, rolling, and aerodynamic drag at 30 km/h seated over cobblestones for varying tire pressure.

Power loss due to vibration at different speeds and tire pressures while seated.

Eloy was supervised by Jason K. Moore and Jim Papadopoulos. Everyone at the bicycle lab is very proud of Eloy and wishes him the best in his next adventures in Sheffield to further study sports engineering.