Shimano dynomo hub question

[MikeF]

The 2N30 is a 2.4watt version as opposed to 3N30 which is 3watt.

[Brucey]

I've had a few 2.4W dynamos in my hands and subjectively they do seem to have lower drag than the 3W versions, especially in the cheaper, draggier (SA, Nexus etc) versions.

2.4W is plenty for riding round town in the UK but they are otherwise meant for the Dutch market; 2.4W is 'the law' over there.

If you attach the right load to them, you can usually get a lot more than 2.4W out of them, of course.

cheers