US standard radius hitch?

Bought an Alumines bumpers years ago. They offer a front hitch wich i got. Never found the need for it until I tried installing my bike hitch rack. It did not fit and when I did research I found out the Aluminess uses US standard radius with round corners. I would like a DIY solution. Should I round the corners of my bike rack hitch part? Aluminess says to use an adapter but not able to find one that doesn't stick out less than 6 inches

 

Its probably easy to modify the bike rack. If its anything like mine (which frankly, I can't see ever wanting to mount on the truck -- after all, its a truck -- bikes go in the bed), then there should be a straight 2" square tube that is BOLTED to the rest of the rack. You would just need to find an appropriately shaped 2" square tube, cut it the right length, drill it in the right places, and bolt it on. Great place to get the replacement square tube is a SCRAP YARD. I tend to go to the scrap yard when I need steel, and in the quantities I buy, the owner typically eyeballs the pieces I pick and gives me a number that I can fulfill out of my cup holder.

And a hint about bike racks; the tube that sticks out of them is typically longer than it needs to be, in order to account for vehicles with varying protrusions beyond the back of the hitch. If you use it on something like, for example, a jeep with its spare tire hanging out the back, then the bike rack needs to stick out further. So you also have an opportunity to customize the bike rack to best fit your vehicle.

If it isn't absolutely clear how to modify the bike rack, then post a good picture of it so others here can give you ideas.