Shimano Hub dynamo - any good?

[David Kerber]

I'm thinking of having a wheel built up with one of Shimano's hub
generators for winter riding purposes. Has anybody ever used one, and
what were your experiences with reliability, power output at low speed,
drag when not in use, etc? The have at least two different versions
with different power outputs, and I am looking at the 3 Watt version.


--
I want to ride my bicycle,
I want to ride my bike.
I want to ride my bicycle,
I want to ride it where I like!

[Andy M-S]

I have the DNH370 or DHN370 or whatever it's called. The '370 model.
I've had it for just under a year.

It's great. I love being able to get on my bike, flip on the lights
and go, no worries about batteries. I do run a battery-powered light
in back, but I almost wish I had the rear light hooked up the generator
as well. It's really cool.

To answer your questions:

1. It's been rock-solid reliable.

2. I run a Lumotec halogen light, and it flickers a bit at very low
speed (slowing down to stop). I keep a white Cateye blinky on my
helmet for this reason.

3. If you try to spin just the hub, it's notchy. If you spin the
wheel with no load connected, it's not quite as free-spinning as a
regular hub, but not bad. If you spin the wheel by hand and put a load
on it, the wheel stops pretty quickly. In actual riding, you notice no
difference.

4. You didn't ask, but...it is significantly heavier than a typical
front hub. That doesn't matter much to me, but I can understand how
some people wouldn't like it.

5. Make sure you get a good headlight. I recommend the Lumotec, for
one thing because it's easy to change the bulb. Generator systems DO
burn out lightbulbs over time (a bit faster than battery systems) so
it's a good idea to have a spare bulb handy. With the round Lumotec
model, I can change bulbs wearing full-finger gloves.

[David Kerber]

Thanks for the discussion!


In article om>,
says...
> I have the DNH370 or DHN370 or whatever it's called. The '370 model.
> I've had it for just under a year.
>
> It's great. I love being able to get on my bike, flip on the lights
> and go, no worries about batteries. I do run a battery-powered light
> in back, but I almost wish I had the rear light hooked up the generator
> as well. It's really cool.

....

> 4. You didn't ask, but...it is significantly heavier than a typical
> front hub. That doesn't matter much to me, but I can understand how
> some people wouldn't like it.

I didn't ask because I don't care <grin>. This is for my tourer, which
is already about 35 lbs with the big steel frame, rack, fenders, fat
tires, aero bars, heavy duty wheels, etc. I knew it would be much
heavier than a regular hub; permanent magnets and copper wire are both
rather dense materials.


> 5. Make sure you get a good headlight. I recommend the Lumotec, for
> one thing because it's easy to change the bulb. Generator systems DO
> burn out lightbulbs over time (a bit faster than battery systems) so
> it's a good idea to have a spare bulb handy. With the round Lumotec
> model, I can change bulbs wearing full-finger gloves.

That's a point I wouldn't have thought of; thanks for bringing it up.

--
I want to ride my bicycle,
I want to ride my bike.
I want to ride my bicycle,
I want to ride it where I like!