The Link Between Roll and Steering Torque in Motorcycles

Steering torque is the most important control input for motorcycle turning; however, some riders believe they can steer using upper body roll alone. As other investigations have shown rider roll to be an ineffective for path control, there is likely a link between rider roll and steering torque in motorcycles. This paper examines new results, looking at the relationship between roll and steering. The specific results look at the connection in two directions. First, results examine how steering torque is generated due to motorcycle roll. Secondly, the rider’s roll and yaw response to steering motion is presented. The results show strong links between motorcycle roll rate and steering, as well as steering and rider motion. The link between steering and rider roll implies the rider can generate steering torque by leaning their upper body. As the generated forces and motions are non-negligible they need to be investigated further. This information, is being used to develop a new model of the rider’s passive impedance. In turn this model can be used to ensure the stability of motorcycles, regardless of the rider.