Originally Posted by BruceMetras

I have one on a Dahon Helios XX.. I like it so much another is going on an XP.. You see them used on Recumbents and HPVs. They can be installed on steel or aluminum bottom brackets of 67-73mm widths and 33.6-34.5mm diameters. It's appears to be made really well, uses standard 110mm chainrings, and I haven't had any problems. It shifts very easily, and there are flat 'extenders' available cheap that run along the crank arm if you want it even easier. For a folder, you'd want the 'SpeedDrive' with a 1.6:1 overdrive or possibly the 'High Speed Drive" with a 2.5:1 overdrive. A 'Mountain Drive' is available, but that is a 2.5:1 underdrive. Attached are a couple of quickie pics.

Bruce