We just came back from a 21 day tour of Sri Lanka with our 20 inch Tern bikes..We had really planned for a backpack tour and taking the bikes was a last minute idea.
As a result we couldn't arrange for bags for the bikes. We just did a bubble wrap with extra protection for the delicate parts like the derailleur, seats and handles. When we landed in Colombo, we unpacked and left the bubble wrap at someone's place to pack the bike again for our flight back.
We bungee tied our rucksacks on our carriers and did around 600 kilometers, in rides averaging about 50 km.
Not the ideal way to do it..makes the bike top heavy and they toppled over a couple of times when we were waiting on some redlighs and I forgot to support the bike upright between my legs..
In a way I was glad that we didn't take the bike bags as they would have added to the luggage on the carriers, and the rucksacks were a great help to keep our hands free during the times we had to fold our bikes and get on trains (the central parts of Sri Lanka are too mountainous to do with conventional folding bikes..need proper mountain bikes for there)
That is also when I realized that it would be great if I had a bike bag made of very thin lightweight fabric..
Sri Lanka has a rule not to allow bikes on passenger and express trains, that includes folding bikes..unless..they're in a bag..!!
We had to often opt for slow trains with.luggage compartment..and pay almost 4 times the amount of our tickets for the bikes..
Lol but those occasions were few and far between..
All in all it was a lot of fun and a great way to know the country and the people.
Now that we are back, I plans to design and make a bike bag that can fold and go into the rucksack's side pocket