The paper presents a theoretical and experimental investigation of sealless pistons with a special profile for reducing friction in pneumatic cylinders. A description of system geometry is followed by the flow rate equations written using a one-dimensional flow model. The axial pressure distribution and the self-centering force on the piston are then determined. The influence of design parameters on system performance is evaluated, and test results are presented for three pistons of the same length and featuring steps of the same height but located in a different axial position. Theoretical results are compared with the experimental data.