In this study, stability of a landing gear mechanism with torsional degree of freedom is analyzed. Derivation of the equations of motion of the model with torsional degree of freedom and the von Schlippe tire model are presented. Nonlinear model is linearized and Routh-Hurwitz criterion is applied. Stability analysis is conducted in the e-v plane for different values of the torsional spring rate c and in the k-v plane for different values of the relaxation length σ and vertical force Fz . Percentages of the stable regions are computed. Effects of the variation of the caster length e, half contact length a and their ratio on stable regions are analyzed. Results and conclusions about the variation of stability are presented and constructive recommendations are given.