When I saw an Alfine 11 hub online for less than half price, I couldn't resist. I had hoped to do an Alfine 11 Brompton conversion at some point, and the opportunity to buy a cheaper Brompton through cycle-to-work brought hub and bike together. I used the bike as a commuter for 18 months, getting used to the Brompton 6-speed set-up.
I knew that Bromptons had been converted to Alfine 11 hubs by others, but in one case with a seriously modified rear triangle. Perhaps that should have been a warning sign. My Alfine 8 conversions had gone like a dream, and I hadn't anticipated that the 11 would be much different.
So I set about working out my gear ratios using the magnificent Brompton Gear Calculator coming up with an ideal spread (for me) using a 16T rear sprocket, and a 40T front chainwheel - made by Stronglight, but Brompton compatible.
For the Alfine hubs, the over-locknut width between the rear dropouts...