A 24" bag is too big. It doesn't matter how you get it into the bin, Chances are you won't get it that far. Gate agents see bags day in and day out. They can spot an oversized bag and won't let it on. More and more airlines are using sizers since they'll be charging for checked bags. If it doesn't fit in the sizer, it gets checked.
Get a 22" bag. STick to 22 x 14 x 9. A few airlines will allow slightly larger but very few.