We traveled with our old coupled tandem in a soft-side case - 26" x 26" x 10". This case is under the oversized limit. We packed the frame & wheels in this case & the rest of the stuff in another smaller suitcase. Both were under the 50# limit. Travelling with a coupled tandem is possible but not easy. We once flew with an uncoupled tandem and it was a real pain. The logistics of getting a box that big through all modes of transportation is really hard (rental cars, shuttles, buses, etc.). If you plan to fly with your tandem, I would highly recommend couplers.