Hey-
If anybody still needs the HiGrip FIRST Wheel CAD, you can get it, as a STEP file, from AndyMark
here. To do so, go under "Files and Documents," then download the "6" HiGrip Wheel CAD File (.stp) (right click, save as)". Once that has been done, Autodesk Inventor can open the file, then resave it in the proper format. It won't be the right material/color, but it is the right shape.