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-   -   dynohub lighting questions (http://www.bikeforums.net/commuting/926056-dynohub-lighting-questions.html)

Pedaleur 12-19-13 05:06 PM

Quote:

Originally Posted by cyccommute (Post 16343672)
Back your statement up. Where am I wrong? Where is my physics wrong? A dynamo hub introduces drag into the bicycle system to produce light. The magnitude is vary slightly depending on which system you use but it is still there and it is related to the speed of the bicycle. The magnitude of the drag once the light is on falls in a fairly narrow band independent of the quality of the hub. Granted the article from Bicycle Quarterly is 10 years old but I doubt that huge advances have been made to suspend physics since then.

And this isn't about "religion" but about data that can be measured and conclusions that can be drawn from that data.

Re-read what I was commenting on. I'm saying that the only people who claim you get "something for nothing" don't understand physics. You're not wrong, but claiming there are a bunch of people out there who say otherwise is disingenuous.

GamblerGORD53 12-19-13 05:08 PM

I've been using a XL-FDD dyno and XL-RD5w for 6000 miles. Extra weight acceleration is slower for sure, but overall probably BETTER. I would say the dyno drag is the same as a mechanical speedometer, a little 1% speck. I've done 45 mph on this 9%/300 yard hill every time. My theory is the mag lev effect at least helps reduce bearing load. My Edelux light is always on. It is far brighter than the old bulbs I had which I used at first with the new dyno, until they burned out.

The bottle generator I had long ago on the other hand sucked 25% of my speed and 99 % coasting at least. Going 20 mph was impossible and reduces tire life likely 90%. They were horrible to even adjust them to work at all.

There is no free lunch with those horrible rechargable batteries either. They go dead in a week or 2 with zero use, wtf ?
Using them with anything but these low load leds is hopeless. Fried Teslas, Dreamliners anyone ??
They are 1.25 volts instead of 1.5, wth ?? Does EverReady,etc have a Patent on 1.5v ??

11 years ago my bike's LBS came out with those 1/2 litre/3 lb pig batteries and the LBS owner couldn't understand why he should even offer dyno hubs for sale ?? WTF. Besides that they would maybe last the whole night ?? LAUGHABLY STUPID !!!!!!!

Pedaleur 12-19-13 05:38 PM

Quote:

Originally Posted by cyccommute (Post 16344202)
But people say all the time that there is little to no drag caused by them which is patently untrue.

Quote:

Originally Posted by Pedaleur (Post 16344229)
Re-read what I was commenting on. I'm saying that the only people who claim you get "something for nothing" don't understand physics. You're not wrong, but claiming there are a bunch of people out there who say otherwise is disingenuous.

Quote:

Originally Posted by GamblerGORD53 (Post 16344232)
I would say the dyno drag is the same as a mechanical speedometer, a little 1% speck. I've done 45 mph on this 9%/300 yard hill every time. My theory is the mag lev effect at least helps reduce bearing load. My Edelux light is always on.

Then again...

no1mad 12-19-13 05:42 PM

Looks like there is plenty of data (both hyperbole and anecdotal) for the OP to hopefully make a decision, along with a fair amount of vitriol thrown in.

Consider this thread closed until further notice.


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