I have two pairs of crossbars (reasons), and don't like to leave the roof ones on, due to wind noise and efficiency. They are a bit cumbersome and take a decent amount of space in the frunk or gear tunnel, so I decided to create a mount that would allow me to store them out of the way.
This is printed in ASA for UV resistance and at 50% infill for strength. There are certainly improvements possible, but these are plenty strong for the task. I can pull extremely hard on the bottom one without it budging. I have no concern about these holding up.
You will need a couple of longer M6 bolts, as the stock ones are not long enough. Any should do fine. You should probably print a spacer, but for now I just turned the stock cup washers around.
The author marked this model as their own original creation.