本文主要探討二輪車之設計參數對其轉向扭力之影響。當二輪車沿著一轉彎半徑穩定行駛同時，駕駛者可透過操控轉向力量之方式以促進車輛行駛之穩定轉向。不過，影響二輪車輛穩定性之因素不只有轉向扭力，尚有其他設計及操作之各項參數。本研究首先對二輪車輛建立分析之數學模型，建構出二輪車輛在穩定行駛轉彎下之力與力矩平衡方程式，再利用系統化方法找出轉向中輪胎之各種作用力。利用本研究之結果，採用不同轉向扭力之分析方法，提供在設計階段選擇時找出最合適的設計參數，使駕駛者可施加較少之扭力於把手上，而仍能轉向中輕鬆操控車輛。

The main purpose of this research is to investigate the steering torque influenced by design parameters of two-wheel vehicles. Neglecting other influences by drivers themselves, drivers of two-wheel vehicles control motorcycles mainly by means of the steering torque while driving along a circular path. In addition, the stabilities of motorcycles are not only influenced by steering torque but also the vehicle design and operating parameters. The reaction forces for steady-state cornering can also be obtained. Finally, by using the method to obtain the steering torque, it can be used in early design stage to determine the design parameters of two-wheel vehicles.