Indeed, the frictional losses are highest in the small cogs, but the middle is the most efficient because of the straighter chainline:
https://www.cyclingabout.com/drivetrain-efficiency-difference-speed-bet… I love big jumps between shifts on a mountain bike, my ideal would be if we had Shimano Hyperglide (or whatever its called) on a 10-50 nine speed cassette, like what Box was trying to do with their Prime 9 but never released. However, on a road bike, I need tight gearing. When you're fighting a headwind or trying to not get dropped when you need to stay tucked behind your faster mate, having the precisely correct...