I wanted to have a way to organize my wheel sets for my RC drift car. I added holes to the bottom of the tube to avoid creating a vacuum. Printed at a .28mm layer height with 5 walls. Quick and strong.

Let the cap cool off before attaching it to the tube. This way it will shrink a little and make a more secure fit. Doing this, I was able to turn the tube upside down, fully loaded with 4 wheels and tires and not have anything move.