The stability and elasto-mechanical properties of tetragonal and cagelike or clathrate nanowires of $\mathrm{Si}$ are investigated and compared using molecular dynamics simulations. Our results show that cagelike nanowires, while possessing lesser density, are able to maintain their structural integrity over a larger range of strain conditions than the tetrahedral nanowires, making them a better candidate for structural strength, chemical sensor, and electronics applications under strain conditions. This could have important technological implications.