GM put this neat composite chassis together for comparison purposes. The left side is old chassis and suspension, while the right is the new chassis. The differences in beef were easily noticed. That beef comes from the boxed rails with larger cross sections, stronger crossmembers and an increase in the yield strength of the steel from 50,000 to 60,000 psi. As a result, the section modulus numbers improved by nine percent, and the RBM (Resisting Bending Moment) increased 32 percent. New hydraulic body mounts are partly responsible for the marked improvement in NVH.