Functional bikes. Not Porn not Anti

What might be interesting (for a given value of interesting) is seeing if the ~200g weight penalty for the clutch over the un-clutched hub evens up the constant 3.3W drag of the hub.

I was interested in this too.

At the end of the day. Plenty of budget dynamo lamps dont even have an off switch. So I liked the idea of being about to 'switch off at the mains' so to speak.

The resistance is huge when spinning a bare wheel (sans tyre). But like Ed points out, its not noticable on a complete tank bike.