Originally Posted by
cyccommute
Depends. If you are talking riding single track where you might have to hike-a-bike for any appreciable time, a dynamo hub isn't practical. Off-road riding is also enhanced by a helmet light...try negotiating a switch back without being able to see into it
Dynamo systems don't work for helmet lights.
While I agree about the use of helmet lights, the capacitors in some models of European dynolights mean you can get several minutes of hike-a-bike time in.
The issue is more that the power output from the hub while grinding up a hill or dodging large rocks for periods beyond that several milnutes means the light starts pulsating with the AC current.