For the efficient development of motorcycles, it is useful to substitute maneuverability feeling, much of which relies upon human sensitivity, with a physical or objective quantity. However, the expression of subjective maneuverability with a physical quantity has been considered difficult because of the significant influence of the human system.
Therefore, an experimental study was carried out to quantify “perceived steer effort”, as part of maneuverability. The input on the handlebar by the rider was quantified using both steering torque and torque at right angles to it in the direction of roll (hereinafter called steer-roll torque). Noting that the handling of a motorcycle can be influenced by rider's motion, the perceived steer effort was evaluated by an increment of torque in the steer-roll torque caused by the rider's upper body movement which the authors defined as “rider control torque”.
As a result, a good correlation was found between the rider's feeling and the changing rate of rider control torque, making the quantification of a part of maneuverability feeling possible.