Mountain bike suspension systems and their effect on rider performance quantified through mechanical, psychological and physiological responses

TJ Mechanical engineering and machinery;QP Physiology

Davie, Mark C. ; Whittaker, Arthur

University:University of Glasgow

Department:School of Engineering

关键词: Mountain bike dynamics;   

Others  :  http://theses.gla.ac.uk/2432/1/2011daviephd.pdf

来源: University of Glasgow

【 摘 要 】

Mountain bike suspension systems have been designed to improve riding performance and comfort for thecyclist. Additionally, a suspension system may reduce fatigue, energy expenditure, and enhance time trialperformance. It has also been proposed, however, that using a rear suspension system on a mountainbike may be detrimental to the cyclist, causing the cyclist’s energy to be dissipated via the rear suspensionsystem.Prior to undertaking the current research, a survey into mountain bike suspension systems was conductedto establish rider preferences, as well as their perceptions of suspension systems and riding styles. Theresulting responses - that the majority of cross-country cyclists chose to ride a bike with front suspensiononly (a hardtail bike), despite the significant advantages that a fully suspended system has to offer – aidedin the decision to address the unanswered questions that remain in this area of research.This thesis presents an investigation into mountain bike suspension systems and their effect on riderperformance, quantifying the dynamic loads exerted on the bike frame and rider. Both the psychologicaland physiological effects of using a rear suspension system on cross-country cycling are additionalconsiderations of this study.An initial laboratory experiment was completed to investigate the effects of rear wheel dynamics on a roughtrack with a high impact frequency and the consequent impact this terrain has on rider performance,comparing a full suspension and hardtail bike. Further testing was conducted on a rolling road rig,specifically designed for the purpose of the current research, which more closely represented theconditions encountered by a cyclist on a cross-country track. Testing was conducted on the rolling road rigon both a flat road and rough track, examining the interaction forces between the bike and rider. Greaterresistance was experienced by cyclists when cycling on the rolling road rig compared to the roller rig whichequated to the resistance encountered when cycling uphill or into a headwind. The mechanical resultsfrom both rigs were compared to dynamic simulations as a means of validating and comparing themechanical results.An additional series of tests was carried out on an indoor track which had a similar terrain to that of therolling road rig. This set of tests placed fewer restrictions on the cyclist as only physiological data wascollected using unobtrusive portable measurement devices, and provided further results to illuminatecorrelations or discrepancies between the roller rig and rolling road rig experiments.The experimental rolling road rig results indicated that, when cycling on a smooth surface, the hardtail bikeoffered no significant physiological advantage to the cyclist; however, more power was required by the riderto pedal the fully suspended bike. This was also advocated by the simulation results. Conversely, it washighlighted that the fully suspended bike provided a significant advantage to the rider compared to thehardtail bike when cycling on extremely rough terrain on the roller rig. This was the case across thesimulation results, mechanical measurements, physiological measurements and psychologicalmeasurements. Similarly, the indoor track tests indicated that cycling on a fully suspended bike providedsignificant advantages to a cyclist in terms of rider performance. On the contrary, the experimental rollingroad rig results on a rough surface demonstrated that no significant difference was apparent betweencycling on either the hardtail or fully suspended bike. This result suggests that, when a rider encountersadded resistance to cycling, as is the case when cycling uphill, there is less of an advantage for a fullysuspended bike even on rough terrain.