Whenever internally geared hubs come under discussion, out come the reduced efficiency statements.
I'm an evidence sort of guy. Is there a study that measured and compared said efficiencies that one can refer to?
And all these gazzilion gear ratios - how necessary are they? I've been commuting single speed and one thing that became clear is that once a suitable ratio is chosen, it works; what's more, on my derailer bikes I use less and less gears. I enjoy standing up to pedal on hills as I become more practiced to do so. Only when I do roadie stunts like TT do I use the whole cassette. So for that application, derailer for sure, but for all other cases? I wonder if we are being spoiled rotten.