Two Wheeler Suspension Tuning with Extended Half-Car Model

Suspension tuning is a very crucial part in development stage of two-wheeler as it addresses two major attributes: Rider comfort and Vehicle Road holding capability. Various analyses like pitch, bounce, unsprung masses behavior, etc. can be done through simulation models before getting on to test vehicles for objective and subjective feel and tuning. Tire being a series element with suspension, plays a crucial part in the tuning because of is radial stiffness. Also, the size of tire matters as it envelops a surface and transmits a modified road profile to the axle of wheel, e.g. a very small pothole almost fully gets absorbed by tire itself and therefore hardly any movement is observed at the wheel axle. In this paper, an extension on half-car model is done which captures the enveloping behavior of the tire over the road surface, as enveloping behavior leads to change in suspension stroke values from what we observe from standard half-car model. A study is also done to understand the approach towards deciding the tire size from ride and comfort point of view. A simulation analysis is done on BikeSim software for the same, vehicle model is correlated with real vehicle data to gain confidence on the analysis. Enveloping behavior is observed using the model and effect on ride, comfort and vehicle road holding capability w.r.t. different tire sizes is presented.