Originally Posted by Duragrouch

I will also add to the Helix/Brompton/X11 debate: Since the patents on the Brompton frame design have long since expired, not only are there clones (aka "Brompnot"), but more importantly, the same frame design adapted to 20"/406 wheels, perhaps even 451 if you look hard enough. Usually these are welded instead of brazed as with Brompton, as 4130 steel welds just dandy. So if you like the Brompton-style frame, and want all-derailleur gearing and a bit more stable and comfortable ride with a wide range of tire selection available, a 20"/406 Brompnot may be your ticket; On 20"/406 you can easily get 400% gear range with either 1X wide cassette or 2X normal cassette, and with both you can have touring-capable gearing at 566% range. Tires you can get up to 2.4" wide I think, which is pretty cushy.