Optimization and Modeling of Mountain Bike Suspension and Pre-load Setting

The initial objective of this experiment was to find the optimal pre-load settings for a mountain bike to minimize vibrations felt by the rider. This objective was refined to developing a predictive model for vibration transmission through the bike at different pre-load settings. Acceleration was measured both above and below the front suspension of a coil-spring fork while the bike was ridden at a constant speed along a rocky path near the UBC Nitobe Memorial Garden to test for frequency response. The system was modeled first as a damped harmonic oscillator, then improved to a coupled harmonic oscillator with loss in account of experimental setup. Model parameters were obtained through fitting to experimental data. The impulse response was tested to find supporting evidence for the model. No significant dependence of resonance frequency or proportion of acceleration transmitted on pre-load settings was observed, and loss values coincide with literature. As well, there is evidence for a weak increasing linear trend in the damping ratio.