One of the biggest PITA's with 2 and 4 bike tray racks is what to do with them and where to store them when they are not in use. I have tried hanging them from the wall with a large C-hook or putting them in the corner like baby but the awkwardness of the design made it difficult. Most people don't leave them on the car for the year so what to do with them?
Well I found s simple solution that could be use a few different ways and that is a 2" Step Bumper Receiver from Harbor Freight that can be mounted almost anywhere. I chose to mount it on a rolling rack but all you really need is a stable platform so it doesn't tumble over which does defeat the purpose. These can be used two way, I went with a flat mount and plan on storing the rack in the closed position. The other way that this can be done is the receiver mount can be put vertical on a wall (with reinforcement) and the rack can be inserted in the open position.
Note: I am showing a 1.25" rack in a 2" receiver with a 2:1.25" adaptor. We use the adaptor for this storage and also using the 1.25" rack on the Yukon.