CRers,
The way I have always set up a wide range double is to have the large ring chainline cheated over as close to where a single ring would be. This allows you to utilise the entire freewheel without needed a front shift. This is great for real world rolling terrain when used with a freewheel geared accordinglly. The inner ring becomes a "granny" of a sort. Not intended in this application to use the whole cluster. This works great for real world rolling terrain and you still have the low gears when needed. My Witcomb USA is set up with a Stronglight 99, 46-28 on a Phil Wood BB with a 13-26 six speed freewheel.
Bill Talbot
New Hartford, CT USA