Abstract : There is today a growing interest for tensegrity mechanisms. Their analysis is however challenging because of their self-stress state. The most popular tensegrity mechanisms use linear springs as tensioned elements. Their synthesis for a given user requirements is an open issue. In this article, we propose as a first step to better understand the influence of the spring characteristics that constitute important design parameters. The influence of spring free length is in particular assessed, considering two planar tensegrity mechanisms. Impact of the spring selection on the workspace, the stiffness and the actuation requirements is observed. The simulation results outline that using nonzero free length springs can be of interest, and conclusions are given on further steps towards a synthesis method.