One-Year Review: Shimano DH-3N80 Dynohub

[GRAVELBIKE]

Posted here (http://www.gravelbike.com/?p=350) on my blog.

[redir]

That's good to know, I've been looking at these hubs lately thinking of building my PHD student wife a wheel for commuting back and forth to campus.

[schwa86]

Have been contemplating building up a wheel -- have to say the back and forth on the web about dynamo hubs is more heat than light (pardon the bad pun).

[GRAVELBIKE]

I certainly don't dislike battery lights, but for day-in, day-out commuting, I think a dynohub is good solution. Choosing the appropriate light can be rather daunting, but the hubs themselves are pretty much set it and forget it.

[Louis]

Link doesn't work for me.

Edit: Works now. Thanks.

[GRAVELBIKE]

Link doesn't work for me.

Fixed it.

[khjr]

Choosing the appropriate light can be rather daunting

Agreed. What did you learn when you went shopping for a lamp and, based on your experience, what would you recommend? If I was to give up my aging and increasingly less reliable L&M Arc, I'd want something comparably bright - (e.g. I sent my Dinotte headlamp back because it wasnt' bright enough) Is that even possible with a generator?

[GRAVELBIKE]

Agreed. What did you learn when you went shopping for a lamp and, based on your experience, what would you recommend? If I was to give up my aging and increasingly less reliable L&M Arc, I'd want something comparably bright - (e.g. I sent my Dinotte headlamp back because it wasnt' bright enough) Is that even possible with a generator?

One thing I learned is more/brighter isn't necessarily better. On many high-powered systems, a lot of the light is wasted due to poor optics/reflectors. Because the design isn't optimized, they have to pump out tons of light so that the usable portion is "bright enough."

The beam shots (http://peterwhitecycles.com/headlights.asp) on Peter White's site are very helpful. It's hard to accurately capture exactly how the beams will look, but Peter's photos are good for comparing the various designs.

Because there aren't any real high-speed sections on my commute, not having a dead spot in front of my wheel was more important than a beam with a longer "throw."

The first headlight I tried was the IQ Cyo R, and I was pretty impressed. Curiosity got the best of me, however, so I ordered a CYO N to see what it was like. It was great for distance illumination, but there was a very distinct dark spot directly in front of the wheel.

Experimenting with different mounting positions also has an effect on the beam shape and efficacy. For me, the best mounting point turned out to be the fork crown:
http://farm5.static.flickr.com/4131/5172824954_b14f0a3d4f.jpg

One other thing I've learned is that brightness/output drops dramatically below 7mph or so. My commute has two slow-speed climbs, so I added a 2W Planet Bike Blaze light to act as an auxiliary light in those situations. Because the dyno-powered light never actually goes completely dark, I can run the Blaze on the low setting for longer battery life. The PB is mounted to a Paul Gino mount on the left-side of my Tubus lowrider rack:
http://farm6.static.flickr.com/5166/5304328086_623119dd84.jpg

Hope this helps.

[Ken Robb]

My SON is full bright before I get to 7 mph. I think you can affect the full-bright speed (not scholarship) by selecting the appropriate hub model within brands.

[John M]

My SON is full bright before I get to 7 mph. I think you can affect the full-bright speed (not scholarship) by selecting the appropriate hub model within brands.

My SON is also full brightness at about 3-4 mph--but the cost diff to the shimano is substantial.

I use a cyo N. The dark spot in front of the wheel isn't a problem for me. After all what is directly in front of the wheel was farther off and in the beam of the light before I got close enough to it that it came into the dark zone.

[BengeBoy]

Nice review.

Coincidentally, I bought the same hub a year ago, used it all winter/spring on my commuting bike, and took it off on the summer. I just got it back on over the weekend and rode if for the first time "this season" today on my commute.

I'm very happy with the purchase. Like you, I can feel the "notchiness" of the hub when it's on a work stand, but I don't really notice it when I'm riding.

I have the IQ Cyo R light, and it really works fine for lighting up my ride. The only thing that has made me nervous is sometimes I get worried that traffic can't see me terribly well because the light is mounted low and to the right.

So, I bought a Planet Bike Blaze light to sit up on my handlebars and flash at oncoming traffic. I know that it sort of defeats the purpose of having a dyno hub but the battery lasts a very long time and I really feel as if in city traffic I need two lights (mounted at different heights) in the front, and the same in the rear.

[John M]

......sometimes I get worried that traffic can't see me terribly well because the light is mounted low and to the right.

So, I bought a Planet Bike Blaze light to sit up on my handlebars and flash at oncoming traffic. I know that it sort of defeats the purpose of having a dyno hub but the battery lasts a very long time and I really feel as if in city traffic I need two lights (mounted at different heights) in the front, and the same in the rear.

I use this same type of combo. The IQ cyo is to see and the flasher is to help being seen on the commute.

[GRAVELBIKE]

It's always a good idea to have secondary light in case one fails. It's especially important for rear lights, as you generally can't tell if one goes out (ask me how I know this).