Derailleurs have, on average, 2% lower loss than hub gears, when new. However, many suggest that because hub gears usually have an enclosed chain, whereas dera

Derailleurs have, on average, 2% lower loss than hub gears, when new. However, many suggest that because hub gears usually have an enclosed chain, whereas derailleurs rarely have an enclosed chain, that 2% is usually eclipsed by chain losses as the chain gets dirty/rusty/worn far faster on derailleurs.