A 3D cycling model is presented that combines bicycle dynamics, a tyre model, rider biomechanics and environmental factors into a single dynamic system. The system is constructed using Matlab toolboxes (SimMechanics/Simulink) with the aim of identifying mechanical mechanisms that can influence performance in a road cycling time trial. Initial conditions are specified and a variable step ODE solver numerically integrates solutions to the equations of motion. Initial validation compared rider-less self-stability presented in a published "benchmark" with model simulation and found an error of <1.5%. Model results included the weave eigenvalue becoming negative at 4.2 m/s and the capsize eigenvalue approaching a positive value at 6.1 m/s. The tyre model predicted peak front tyre slip and camber forces of 130 N and 17 N respectively which were within 0.9% of values reported in the literature. Experimental field validation compared actual and model predicted time taken by 14 experienced cyclists to complete a time trial over an undulating 2.5 mile road course. An error level of 1.4% (±1.5%) was found between actual and predicted time. This compares well with the average 1.32% error reported by existing road cycling models over simpler courses.
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