This study considers the effects of several parameters on the force/moment systems produced by T-loop retraction springs. The springs are studied by using the finite element method and by experimentally measuring the forces and moments from the various designs. The results show that varying the spring height can produce larger moment to force ratios as the height increases. Changes in the preactivation bends result in unsymmetric moment characteristics and also produce large intrusive/extrusive forces. The addition of helices at the bends did little to alter the springs' mechanical characteristics.