I'd like to install a drum brake on a Brompton.
The internal distance between the drop-outs is 74mm.
I don't know how wide the Shimano Nexus Roller Brake are, but Sturmey-Archer's X-FD looks interesting.
However, I'm confused about its dimensions: The page says it's 70mm while the PDF says its OLD is 100mm.
Can someone confirm 70mm is actually the width of the drum brake vertically, and 100mm the distance between the two flanges, ie. it won't fit on a Brompton?