Folding Bikes - Narrow hub spacing and dynohub options

What is the spacing on the narrow hubs out there?

It looks like my Tikit uses 74mm spacing.

I can't tell if the Brompton and Dahon hubs are both 74mm too, or if they use different widths. This would help me determine which hubs will work for me.

What options do I have for dynohubs besides the SONXS? Dahon makes the Joule (looks like a relabelled Sanyo/Shimano?), but it doesn't appear to be sold in the US. SRAM recently announced a narrow dynohub (D3 is available with 74mm spacing), but I don't think this is sold in the US either.

I'd prefer a QR axle (a downside to the Joule, it is nutted).

What are other narrow front hub users doing?

alex

What is the spacing on the narrow hubs out there?
Brompton ~73mm
Dahon ~74mm

Petter White sells both Schmidt and Shimano Dynohub's. He has lots of good info on his web site about them. He was a lot of help on the phone when I added one to my bike.

http://www.peterwhitecycles.com/index.html

Not addressing the question of width, bear in mind that most dynamo hubs are designed for 26" - 28" wheels. The SON20 is an exception, and the Dahon Joule may be an exception as well. As far as I can tell the Sturmey Archer Dynohub in my wife's Raleigh RSW-16 also puts out a comparatively low voltage, suggesting it was calibrated for the small rim. But in a 16" wheel a Shimano Nexus hub, for example, would rotate much faster than intended, resulting in high voltages, which may be very bad for the electronics. It's not necessarily a problem; you just have to be aware of it and deal with it, with a voltage regulator circuit and that kind of thing. I have a Nexus HB-NX30 hub in my DT Mini and am quite happy with it; it runs 12 volt 5 W halogen bulbs quite effectively, along with a tail light from Pep Boys (the 12 volt system opens up the world of automotive accessories, which is kinda cool!).

Not addressing the question of width, bear in mind that most dynamo hubs are designed for 26" - 28" wheels. The SON20 is an exception, and the Dahon Joule may be an exception as well. As far as I can tell the Sturmey Archer Dynohub in my wife's Raleigh RSW-16 also puts out a comparatively low voltage, suggesting it was calibrated for the small rim. But in a 16" wheel a Shimano Nexus hub, for example, would rotate much faster than intended, resulting in high voltages, which may be very bad for the electronics. It's not necessarily a problem; you just have to be aware of it and deal with it, with a voltage regulator circuit and that kind of thing. I have a Nexus HB-NX30 hub in my DT Mini and am quite happy with it; it runs 12 volt 5 W halogen bulbs quite effectively, along with a tail light from Pep Boys (the 12 volt system opens up the world of automotive accessories, which is kinda cool!).

Good point. The thought never crossed my mind.

The new Birdy's also have narrow spacing. What dynohub does it use for its "City" or "Touring" version?

-G

Petter White sells both Schmidt and Shimano Dynohub's. He has lots of good info on his web site about them. He was a lot of help on the phone when I added one to my bike.

http://www.peterwhitecycles.com/index.html

I've bought a lot from Peter before, but the only 20" dynohub that he offers is the SON20 and SON20XS.

Shimano and SRAM also make 20" dynohubs, but they are harder to find in the US. I was hoping to find one.

Thanks to the others who said that Dahon and Birdy are both close to 73mm. The difference between 73mm and 74mm is minor (and below the tolerances that most forks are built to) so a hub built for one should work in the other.

Has anyone used the Dahon Joule? It might be the easiest to get non-SON option.