Go to a local bike shop and get a box or two or three. Generally, they are free for the asking. Take them home and begin practice.

Disassemble the bike or remove skewers from wheels. Fit the disassembled bike frame and wheels into the original box and mark where the minimum length will be, based on the stuff in the box. Now, start to work. You want to preserve one end and one side untouched at first. I do not know how to describe this part of the process to you, hence the need for a few boxes to practice on...



You will need a tape measure, a Sharpie, or pencil or anything that marks, an Olfa Cutter, some packing tape (2 mm preferred and use lots), and something to crease with (I use the dull end of the Olfa cutter to crease the cardboard).


Solid lines are cut lines, broken lines are fold lines...







Define width once end is cut and end fold is made...



Before you fold the prepared end into the box, you need to crush the bottom of the folded end to clear the inside of the box...




It is really not all that hard to make the box fit. Just start, do one thing and then figure out what needs to be cut or folded next. Shorten the box appropriately and then decrease the height appropriately. This will be trial and error but you should figure it out before you get to box three.

Give it a shot. Get a cutter, packing tape and a few boxes and away you go.