I'm a clever bugger!
 

I'm a clever bugger, made some box wheels....since we are going on a trip with plenty of stop overs, long transits, buses and etc. We'll ditch the boxes at our starting point, Athens, mail the plates to and pick up new boxes in Venice.

They're strong enough to for me to be able to sit on the box. That's good, means we can chuck our bags with panniers inside on the top of the box and wheel the lot along like a giant suitcase.https://cimg7.ibsrv.net/gimg/bikefor...ded4fc3cee.jpg
Internal piece with rivnuts, external piece with wheels. One internal end has rubber padding for the forks.
https://cimg9.ibsrv.net/gimg/bikefor...535e0a99ac.jpg

Makes a sandwich of the box, clamped with wingbolts.
https://cimg0.ibsrv.net/gimg/bikefor...392ba5d67d.jpg

Clamped onto the box. The internal plate has double sided tape to hold it in place, there is extra unused for the return trip box, I'll use fender washers and bolts to hold the internal ones when the wheel plates are off, after check in (I don't trust the baggage handlers not to knock the wheels off so I'll remove them)

Nice! Maybe duct tape a handle onto the other end?

Got the wheels on both ends. I usually reinforce the box handles with fabric though. Some wood glue and strips of cloth so the baggage handlers can't rip the box open.

Great idea! A question? Do you have to unpack the bike box to install part of this setup?

Not once it's installed, there's some double sided tape on the inner plate to hold it. I'll probably put a couple of bolts with fender washers in each end, to be sure... will help protect the box, those baggage handlers love dragging boxes around. At the very least they'll make a horrible noise when dragged across concrete. If weight wasn't an issue with my bike (it's a stupidly heavy expedition bike) I'd make some way to leave the outer plates on and just unbolt the wheels as it is my bike weighs 21kg empty....fark. Thanks to a Rohloff and an ATS speed drive, 3 kg heavier than my partners almost identical derailleur bike.

Yeesh. Well at least you know it should last you through most anything, and be pretty trouble free!

Ive generally found that trollies are available always at airports, and when there havent been, surprisingly enough, the floors in terminals are usually smooth enough that Ive been able to push the box along sliding and it works ok.

so when arrive at the point where you will leave your box, will you only remove the wheels? From the outside and leave the plates on for the flight?
You did say it will make a scraping sound when dragged, so thats why I picture it without wheels on but the plates still there.

good idea on the cloth and glue for "handle holes". Ive always put bits of tape to reinforce these areas, and its generally been ok, although the handles have gotten ripped a bit a few times, but liveable.

with your bike at 21kg 46lbs, that is heavy, a good deal more than my Troll, 14-15lbs more, so that does make a difference for schlepping the box on its own if a trolly isnt around, so I can see why you came up with an easier solution.

all the best with safely packing the bikes, Im sold now on the "zip tie the front wheel into position" so that the tire goes up against the crank area and headtube area, and the zip ties keep in firmly in place so that the front hub is safely in the frame triangle dead space, and cant ever move against the frane.

Judicious placement of foam bits are key also.
touch wood

For the last bunch of trips, Ive even brought some of the key foam bits with me, as I have space in my large rackpack ontop of my panniers, and they weigh nothing. I also bring extra zipties with me also, again just handy to not have to source them and the number of grams of all this stuff is really really small.
good luck with the flights and baggage handlers (touch wood again)

The outward leg of this trip ends up in Athens, Greece, with a bus trip into the city at some ungawdly hour of the morning, then hanging around until 3pm when we can check in to our accommodation which is a few km from the bus station, so will probably involve another bus trip. Plus a stop over in Tokyo on the way with a couple of bus rides so mobility will be a plus. Then there's the flight from Venice to Helsinki and a tram trip into town and back out again.

I'm now planning to squeeze 5 pounds of mud into a 10 pound sack as well. I've figured out if I pull the bikes down I can fit them in a modified box that is under the Japan Airlines large luggage limit which is 203cm total, saves 20000yen , which is around US$190, per bike per leg . Sucks though, fenders off, handlebars need to have all the controls removed, bottle cages off, racks off, forks off. Wheels out, which is a bona-fide PITA with the Rohloff, which will now leak oil everywhere without the skewer in. Box ends up being 76x21x105cm. But for $380 extra each way I'll do it. At least there's so little room in the box nothing much can move around.

re box dimensions, cardboard boxes sourced at bike stores can vary in sizes depending on frame size bike they receive. One of my last ones I used was 148x19.5x82 and was a reasonably easy fit for the medium troll, with rear wheel, rear rack and rear fender still left on, front wheel and front rack off obviously, and seat post pushed all the way down and seat was still a bit below top of box.
I tend to put my sleeping bag or tent upnear front fork, which always has good sturdy plastic piece in dropouts, taped on and some added foam taped under as well for shock absorption.

Ive also used slightly smaller boxes in the past, which were a bit of a pain to get bike into, but specifically wrote down these dimensions, from a box from a bike store in Mexico, and worked fairly well fitting in wise.
Ive never had them actually apply and measure for the "official" dimensions limit of X+Y+Z, could it happen? I dont know, but as I have always arrived with a clearly official bike box with bike brand logos on the side, and they are accustomed to seeing bike boxes, its never happened to me so far (touch wood).
Ive only flown Canada to France, to the states, and to a few places in Latin America, with (overall) bike friendly ish airlines with reasonable rates for bike boxes--as long as you respect the weight limits, which I have always been under or just a bit close to limit, but always under.

Any other airline than JAL would be fine. Their baggage allowance is two pieces at 23kg, which is unusual for outside of the USA (or flights to the USA) but they are ruthless with the tape measure because rules are rules in Japan, unless they aren't (but mostly are), and I've had our boxes measured by them ,even though they were clearly oversized luggage so why bother! Anyway, it'll be entertaining getting my bike with the Rohloff and ATS speed drive in there. The derailleur bike will be fine, it has self extracting cranks but the ATS cranks are hard to get off easily.

Well I did it, got the bikes into the boxes: 105 x 21 x 760 Have to carry my seat and suspension seat post separately, the extra weight of the Rohloff means it's over the 23kg limit. Will be entertaining arguing with the check in in Tokyo I bet. The Rohloff was a PITA as well, you have to pull the external transfer box off to get the disc off, then put it back on, otherwise all the oil leaks out. It'll leak slowly anyway, since the skewer isn't in.
https://cimg2.ibsrv.net/gimg/bikefor...ac38c40dd3.jpg

Thanks for explanation and photos, complicated.