Dynamo front hubs, anybody ever use one?

[Dr. Tankenstein]

Just doing some research here...... I want to run a front drum/band brake hub on a bike I'm building. In my search, I found the Sturmey Archer X-FDD (70mm drum brake) and XL-FDD (90mm drum brake) hubs. Not only are they the right type of brake for me, but they generate either 2.4 or 3 watts.

So.....anyone have experience with these or any other brand of dynamo hub? If I plan on powering some LEDS is it better to run the 2.4 or the 3 watt version?
Also, is there any true advantage, besides not having to repace batteries, running these hubs? Is there drag or a noise from running these?

Drop some knowledge on me brothers!

Cheers,
Dr. T

 

[deorman]

There is a very slight drag, nothing you'd notice.

 

[rydr1]

My Felt MP has one on it. I wouldn't say there is a drag on it either. Its connected to the stock headlight and from my experince it is a bit dim, but of course that can be remedied by installing a better light and bulbs.

 

[c.p.odom]

Of course there is drag that is how it works. The drag should not be mechanical friction but a magnetic resistance.

 

[StephenH]

I put a generator hub and headlight on my bike for randonneuring.

Disadvantage: Cost. I've got a $700 light on a $900 bike. That's a Sun Delux 20 or something like that, with an Edelux light.
Advantage: You can ride all night, see the road, and not run out of batteries.
Drag is so little, I can't tell if the light is on or off that way.

I had a Magicshine, which actually puts out more light, but wouldn't last long enough for a 400k, and the 2-AA type lights weren't bright enough.

WHen I was a kid, I had a bottle-type generator, and it had a lot more drag and a lot less light.

 

[user 135]

Here is some good write ups about Dynamo's. http://swhs.home.xs4all.nl/fiets/tests/ ... dynamo%27s

Of particular interest is the Swithchable one where you can turn off the power generation. Velo Orange had one of these but took it off the market due to a poor assembly process. http://swhs.home.xs4all.nl/fiets/tests/ ... ex_en.html

He doesn't test any drum versions though.

 

[Dr. Tankenstein]

Thanks for all input guys! Question (as I write this, it's probably a stupid one, but anyway..) do the lights continue to work when you stop or would I need to wire up a capacitor to hold the charge. Or would I need to buy a light with it built-in?

Thanks for the education!

Cheers,
Dr. T

 

[wimpy]

As far as I can tell,if the light is only hooked up to the dynamo hub,it stops shining as soon as you've come to a halt. Unless you've got supportive batteries,to hold the power (which are charged by the dynamo-hub). Correct me if I'm wrong.

 

[deorman]

There are capacitor systems which remain lit for a short time when you stop. Usually just a rear marker because headlights use too much juice. You could use a cheap led flasher for visibility when stopped.

 

[Dr. Tankenstein]

The responses have been very educational and I appreciate the feedback from everyone, but...

I'm leaning away from this idea, I think.
Not sure if the added expense is worth it, for me anyway.
Besides, with LEDs and inexpensive rechargeable batteries (and my limited skills :roll: ) I can come up with a solution.

Thanks again!


Cheers,
Dr. T

 

[wimpy]

It looks more difficult than it is,fixing a headlight with LED's,batteries and a switch. I'm a dweeb myself,when it comes to electrical stuff. But even I managed,Dr.T. I found a multiple-use LED lamp,soldered 2 wires from a swich to the lamp and put it completely in a moped's headlight. Half an hour of work and 5 Bux,that's all it took. If you're interested,I'll post a few pics. Tomorrow that is,'cause I haven't taken any yet. :mrgreen:
How often do you need your light? I don't cruise in the evenings,so I wouldn't need a dynamo-hub. A battery operated lamp is enough for me.
How 'bout you?