MagicBox, I’m InterBlog’s other half. I’m not on the forums much, but will try to answer.
The photo above contains basically 3 separate parts. A hinge with pop pin, a latch, and a pair of receiver tubes.
Comp4x4 sold the best hinge on the market but they don’t appear to have survived the Covid shutdowns so I can’t point you to their website anymore.
But their blogger page is still up and has a series on selecting hinges for constructing a tire carrier but many image links are now dead on some of their other posts.
Most Important Components Part 1
Most Important Components Part 2
Most Important Components Part 3
Here are some reference images (mostly off Pinterest):
Similar style Pop Pin used in a similar application:
Another Pop Pin during fab:
Note the vertical orientation and the shim that the end of the arm is sitting on. Most mount these latches horizontally but the vertical orientation still locks the arm in place so it can’t swing while driving but also ensures solid contact with the shim under the arm so any vertical loads while on the road are transmitted back to the bumper frame and not through a big moment arm to the hinge spindle.
Here is a nicely fabbed tire carrier using a similar dual shear hinge but with the pop pin and plate on top. I’m not sure how or if they retained access to the hinge bearing retainer nut:
Here is a close up pic of a smaller Comp4x4 hinge:
As for the dual receivers, I had intended to weld them onto the sides of the Sprinter’s reciever plates:
This would allow the carrier to have two prongs (like a fork) to attach to the van instead of one big twisting moment in a single 2” receiver.