Same basic flooring construction as mine except concrete columns are assembled with concrete blocks.

I guess it depends on the tire's physical properties, though whatever it is should in theory be matched at the front. FWIW, my ~20 ft^3 cabs have rigid, high durometer rubber casters at the bottom rear with handles higher up for some ~back friendly mobility even up/down steps with a helper, so only contact the floor if tilted back a bit. The bottom has a thin sheet of cork like used to line tool chest drawers to allow them to be slid around on the floor for minor position adjustments or move them out of the corners enough to gain access to the handles.

GM