Six five-degree-of freedom models and a ten degree-of-freedom model incorporating frame rigidity of motorcycles have been developed. The models include torsional rigidity of the main frame and rear swing arm in the rolling direction ; torsional rigidity of the front fork in the steering direction ; and lateral bending rigidity of the main frame, front fork and rear swing arm. Computational results using the models, including damping properties and natural frequencies of weave and wobble modes, are presented, discussed and compared with experimental results. Conclusions are drawn about effects of frame rigidity on the stability of motorcycles during straight running from the calculations in the five degree-of-freedom models. Implications for accurate modeling of motorcycle stability are derived from differences between the calculations in the ten-degree-of-freedom model and running experiments.