In this paper, kinematic models of front-wheel-drive / rear-wheel-drive wheelchairs are derived to represent the differences in drive stability and operability between the two types of wheelchair configurations. For the purpose, we introduce an offset between a human position and the rotation center of the wheelchair. By varying this parameter, the front-wheel-drive or the rear-wheel-drive can be clearly defined in the kinematic model. Addition to the kinematic model of the wheelchair, we build a human operation model which includes the offset. Performances of the wheelchairs to track a straight line are analyzed by simulations using MATLAB/Simulink and compared with experimental results. From the study, we successfully found instable characteristics in the front-wheel-drive than the rear-wheel-drive.