In a 4-wheeled suitcase, there are three possible ends to put the wheels. Most commonly, the wheels are at the short end:
I find it hard to keep them on 4 wheels; one has to push, and if there is the slightest obstacle (such as tiles), it tends to topple over.
Rarely, the wheels are at the long end:
Source: Bet Bath and Beyond
I've never used such a suitcase.
They could be at the large end, essentially like a cart:
Source: RDM Industrial Products
I've never seen that design in a suitcase.
Why do 4-wheel suitcases usually have the wheels at the short side, rather than at the long side, and never at the large side?