Originally Posted by
mommus
If you had to walk through terrain unsuitable for a bike, or if you wanted to carry it on a plane, train etc. It would be nicer to pack inside something rather than having all the protruding bits scraping and catching on things. I'm not suggesting anyone treks through the Amazon rainforest with it but foldies do need to be carried from time to time, and the most convenient way to carry something heavy is on your back... well, actually the most convenient way to carry something heavy is to get someone else to carry it, obviously.
The reason, IMO, we don't see more folders intended to be carried on the back is that having those protruding bits jabbing your back is far worse than having them scraping and catching on other things.
This can be solved by covering or eliminating the scraping bits, but any kind of casing or shell will make the bike so heavy that it defeats the purpose of carrying it on your back and unless all the parts are custom made there will surely be many such bits. So there are weight and cost constraints.
There's also the issue of how far the bike protrudes behind the back. A very thick pack pulls more backwards than down and taxes the stomach muscles more than the back muscles, thus defeating the goal of using the strong back muscles to do the work. It's very difficult to build a thin folder...particularly because of the bottom bracket and pedals. Perhaps a Gram Obree style washing machine BB would help here, but so far no one has tried it and it still doesn't solve the jabbing problem.
BTW, speaking of Gram Obree a lot of his design elements are either the same as or improvements for folding bikes (monotube frame, smaller Q factor, etc) and are faster to boot. I'd like to see old faithful redesigned as a folder and I'd be surprised if Rob English hasn't had the same idea:
