Dunno.

What I’ve noticed – fer sure / on all flavors of Citibike: considerable variation in how easily or not-so-easily the bottom bracket spins. Try spinning the cranks backwards while you’re coasting. (Guaranteed to puzzle most folks who see what you’re doing.) I’ve no doubt about the bottom bracket thing. I’ve never taken the time to check how freely or not-so-freely the front and rear wheels spin on bikes that seemed more difficult to pedal.

I’m not surprised (and I’m not complaining) about maintenance variations in Citibikes that are fundamentally serviceable. Which doesn’t address the unanswered question about occasional variation in range available on the NuVinci-equipped bikes.