I purchased this to go on a trip.  Leaving for the airport, I noticed it was falling over.  I had to put up with that throughout the whole trip, which was very annoying. It just wouldn't stand up.  I believe mine had two wheels.  I returned it as soon as I came back from trip.  I still have the brochure that came with it and that shows four wheels, so don't know why mine only had two.

I would get a different carryon and test before going on a trip.