Contents slumping is definitely the elephant in the room that no one likes to talk about. if your luggage gets bumped and thrown around enough, straps and packing cubes will succumb and shift out of place. eBags has the best solution with their mid compartment divider panels on their Mother Lode backpack line - but for other reasons I don’t like them. It would be great if Steves Back Door included similar optional mid main compartment dividers. Steves approach is very traditional - use stuffed cubes and then the included interior straps to cinch them down. Unfortunately heavy cubes that are higher up (in backpack orientation) can still wedge their way to the bottom.
There are only two sure-fire solutions:
Overpack like crazy. This is not a solution, it’s a problem. But it’s true that snugger contents shift less.
Or put denser articles on bottom, lighter but bulky items like parkas and jackets on top.
So (crushable only!) shoes on very bottom, dense clothing cubes next up, bulky puff jackets at top.
The one caveat is: many daypacks in the 30L range can be stowed over head the same orientation they are worn. The Steves Back Door convertible suitcase, however, is carried vertically but stowed horizontally on edge, nose in first.
On edge overhead for just one flight won’t shift things too much. Carrying by the side handle will, though. All the jostling from walking. Same in the back.
Finally, consider cinching the bottom of the Steves very tight, then putting a narrower packing cube crossways over the bottom contents of the bag. That should help stop cubes toward the top end from wedging their way downwards, sliding past the bottom cubes.
I’ve come to the conclusion that the already large Back Door is at its best only when packed to the hills. Even then there will be some slumping. Which is why we don’t bring it up.
