greyingbeard wrote:I was wondering about how good the bottom connection is, but with USA litigation costs, surely it must work ?
'work' and 'work well' are two different things; if the manual says to inspect the connection before each use and to retighten it at intervals then the manufacturers are covered even if the system is a POS that breaks and/or regularly works loose as you ride down the road. Which it might well do, for some (strong) riders; the reason why S&S couplings are made more like Hirth couplings is that the down tube in particular sees high torsional loads in most diamond frames. The Fubi arrangement has no appreciable torsional stiffness designed into its down tube, and the 'breakaway' coupling is reliant solely on friction in the coupling in order to transfer torsion loads; this may not be entirely reliable once the coupling has seen some wear.
The whole attraction of folding bikes with full-sized wheels is that they might ride like 'normal' bikes, not like most folders. However this is (IMHO) almost completely pointless if the frame is rendered in such a way as it flexes in use in an abnormal fashion. The FUBi is clever enough, but the nub of it is that there isn't very much point in making the folding frame fold much smaller than the (large) wheels are, since this is the thing that always limits the package size when the bike is folded.
This being the case if you want the frame to ride like a normal bike (and you are not using S&S couplings) this is best achieved by keeping the main triangle in the frame intact; The Rudge (Montague) BiFrame is like this, and so are others such as any Rinko package or bikes such as Rob English's suitcase bike design. In fact Rob English's suitcase bike design ought to be one of the best; provided the BB shell clamps are made properly the chainstays shouldn't flex abnormally and the bike should ride like a 'normal' one.
A few bikes (the BiFrame being one, and the Fubi being another ) have a 'quick fold' (which might be suitable for some public transport or a car boot) as well as a more extensive fold which takes longer to accomplish. The danger in this is that the bike can fall between two (or three) stools; if either fold is compromised by the other, or by the way the bike rides, the whole thing may be a poor compromise in every respect, rather than at least being 'good in parts'.
There is no such thing as a perfect folding bike; it is a case of 'choose your poison'...?