nAn evaluation of the Chassis Torsional Stiffness will be acceptable with all the joints set to Fixed.nIf you allow the A-arms to be loaded with a spring, and to deform when applying load to the wheel axle in an attempt to deform the chassis, well, now you have two springs in series, the A-arm spring and the chassis equivalent spring stiffness. Why would you want to muddle them together. The spring rate on the A-arm has nothing to do with the chassis stiffness, does it?n