Experimental Study on Effect of Damper Lag on Motorcycle Ride Comfort

Damper lag and hysteresis are important parameters affecting the dynamic response of the hydraulic shock absorbers. The response of the suspension unit to road excitation strongly influences motorcycle ride comfort. Overall ride comfort of a motorcycle, under various operating conditions, is a result of very complex system dynamics, where the damper dynamics has a major share. This makes it imperative to include damper lag as a critical parameter for ride comfort optimization. Analytical models are available to predict the dynamic behaviour of a hydraulic damper, however their ability in capturing the lag and hysteretic characteristics is limited. Capturing such dynamic phenomenon through mathematical modeling can become very intricate and involved, thus making the task of analysis and simulation of ride comfort further complex.

Literature available on experimental research in establishing the effect of damper lag on overall ride comfort is found to be very limited. The current paper investigates the effect of damper lag of the rear shock absorber on ride comfort of a typical motorcycle. Experimental quantification of the damper lag in terms of energy loss is attempted. Damper design is varied to achieve different degree of lag and assessment of its impact on ride comfort is done experimentally. Subjective and objective assessment of the overall ride comfort is done on the experimental motorcycle, over typical ride track surfaces with the different dampers produced.

Damper lag is shown to have substantial effect on ride comfort. The relationship between damper lag at various levels and the associated discomfort is quantified. The ride comfort improvement achievable with reduced lag is established through hypothesis testing.