I am trying to show displacement for a frame in Solidworks, and I am putting forces on two points where front wheels would be located. I do not want the arms holding the wheels to take any of the force, so I want to treat them as trusses. Whenever I do this, the test fails because the model is unstable. It works just fine when they are treated as beams, but they hold a majority of the force. What do I need to do to make the test work with those forces as trusses?