Tube Material Grade
In the HIBS I rear structure design, the material of the tubes was primarily DP800. Because the tube gage was already low, the material was not increased to DP1000. To take as much weight out as possible, in HIBS II, the material grade was increased to DP 1000 to understand its effects on weight.

Tube Gage Optimization
Through optimization,
the hydroformed rear
rail was broken into 2
areas. This rail is
already highly optimized
(common gage
throughout). However,
there was some weight
reduction by reducing
the gage of the front
portion of the rail.