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22

The electric parts of the dynamo hub don't care. They're an AC generator and there's no concept of reversing the flow with AC. However, the mechanical bits of the hub itself can be a problem. You don't indicate which manufacturer/model dynamo you have. The great majority of hubs are constructed such that they are expecting the wheel to turn in a certain ...


11

There are standlights, which are essentially supercapacitors combined with LED headlights. They're designed to be charged from the dynamo while riding and give you a few minutes of extra lighting when stopped at a stoplight. However, all the ones I know will self-dissipate after a while, so they're useless for your purposes of starting off the day with full ...


11

This happens because the power from a hub dynamo (which technically is a magneto, not a true dynamo) is not clean sine-wave AC but consists of short pulses with alternating polarity. At high speeds these pulses follow each other fast enough that a LED can burn continuously with a small capacitor and a filament bulb does not have time to cool down between ...


11

Generator hubs for small wheels will output less and produce less drag at a given speed when built to a 700, because they'll be operating at fewer RPMs than expected. AFAIK all the non-sondelux Schmidts still have output suitable for halogen, including XS-M. You should double check when you order the hub. If so it will pair fine with LED in a larger wheel.


9

Here's a guide for overhauling a cup-and-cone low-end Shimano dynamo: https://dl.dropboxusercontent.com/u/34057344/Overhauling_Shimano_Dynamo_Hubs.pdf The main caution from that article concerns the connector-side cone & nut and the aluminum wire underneath them: Using your finger to prevent the plug assembly from turning, break the lock nut from the ...


9

Bottle dynamos aren't actually as bad as often claimed. They are usually cheap, lightweight, have less resistance than people think and zero resistance when not in use. There are some bad parts, though: Most of available dynamos are complete rubbish and won't last in use. High quality dynamos have been superseded by hub dynamos and battery lights. ...


8

You should replace the rear wheel only if there is another well justified reason to do so, but generally both wheels are mostly independent, so you can perfectly change only the front. The first scenario I think of is where you are changing only the front hub (and spokes) and keeping the front rim. Why would you change the rear one? Easier task is to ...


8

Simple idea - turn the wheel over in the truing stand. The low side of the rim should move to the other side. If the Right-hand side is still low after flipping, your gauge is out and needs calibrating.


8

The truth is, that the vast majority of bottle-dynamos are utter crap. They are built to be attached to BSOs (BSO = Bike Shaped Object, a bike that's built so cheap that you can hardly call it a bike), allowing the BSO to pass the legal checks (needs to have working lights compliant to law), but are simply not designed to cope with low temperatures and/or ...


8

Reelight do something similar but opposite: they mount magnets on the spokes and the light and coils on the frame. This demonstrates that it's broadly possible. You'd need to mount the magnet on the fork or seat-/chain-stay with a coil and light on the wheel. This gapped dynamo arrangement won't be very efficient, but wheel lights don't need to be as ...


8

Reverse pulses at low voltage probably won't damage the LED, but the COB (chip on board) that gives the flashing modes might not be able to cope with the full reverse voltage. The problem is that the hub dynamo is more accurately a constant current source, and will supply about 500mA. One common trick is to run two 6V lights in series off a hub dynamo, and ...


8

Remember a dynamo hub has a small electric generator inside of it. What you are feeling when you turn the shaft is the interaction between the magnets and wires in the the generator creating peaks of torque on the shaft.


7

When checking a Dynamo system, there are 3 basic items which need confirmation: Power Supply: Is your dynamo producing power? Checking this requires a multimeter, preferably with alligator clips on the wiring, and to spin the hub. Or there are specific tools, as well. Wiring continuity: Are all connections tight? Are there any breaks/shorts in the circuit? ...


6

Well. I think that you really want this you have to build something youself. Basically you will need a light without a condensator and this circuit. Just add it to the power cable and have fun. http://www.instructables.com/id/LED-flashing-circuit/ IMHO flashing lights are not optimal because they reduce the ability to gauge distances. A better approach ...


6

I have an Origin rear light and I've seen that it can be charged via usb and also have the lights on at the same time. If you want to have it powered by a Dynamo, what you could do is have the Dynamo connected to it the whole time on the bike and be lighting at the same time. That could be a way to pull it off and never have to take it off. Also, if you ...


6

Taking 100kg of bike plus rider up a 0.3% grade generates a retarding force of 100kg*g*0.003=3N. At 24 km/hr=20/3 m/s that is 20 watts. If that is generating 1A at 5V, the efficiency is 25%. Yes, I picked numbers that were easy to calculate with. But I believe this is all marketingspeak and you shouldn't trust the numbers to an order of magnitude. ...


6

I have never owned the cheap and nasty dyno hubs you're looking at as alternatives, only the SON hub. My experience of the SON is that it has not been necessary to ride gently, and observation of other owners suggests they don't do that either. I've owned mine for more than 10 years, and done enough distance that I felt it necessary to have the bearings ...


6

I use ShoeGoo or Sugru (you can Google both brand names) for waterproofing connectors. The advantage of both is that they are flexible and waterproof, but also relatively easy to remove in the field without any gooey residue (which tape tends to leave). I also find it hard to use shrinkwrap to waterproof connections where the diameter of the two parts is ...


6

I've used such wheels for some time on my hardtail. First with V-brakes back and front, then switched to disk brakes as the frame allowed both types of brakes. I cannot say that I have experienced any issues with such wheelset. My centerlocks hubs even came with plastic covers on disk mounting surfaces so that they would not become dirty when no disks are ...


5

There aren't many repair or maintenance parts on a Shimano dynamo hub. At best, you can replace the sealed bearings (on the units that have them) or adjust the cones on the ones that don't. The most likely failure mode in your case is that either the 1) main electrical leads have oxidized; 2) or an internal wire has broken. My guess is that since your ...


5

There is very little to do with this hub. Mostly you need to tighten brake cable. Edit. After 2 years of everyday use with 7-30 kilometers per day in city traffic with lot of junctions, using front brake as main brake (est. total 10 000 km) in my case there is still a lot of ( ca. 60-75%, didn't measured exactly) brake lining on my X-FDD brake ...


5

Thought I should update this just in case anyone's been looking (probably not so much in summer!). I got a good deal on a B&M Cyo plus. This has a switch and standlight. The rear light connection is switched AC. I bought the cheapest standlight equipped rear light I could find with no switch. The front light comes on and off with the switch as you'd ...


5

According to this page yes, the hub is discontinued and is no longer available @armb's assumption may be true. They stopped making IGH's and dynamo hubs for the same reason, at the same time. I-light had such a small market share that it didn't even earned to be mentioned.


5

Speaking in terms of past few decades to current generator hubs and lights, mostly they are interchangeable, with some qualifiers and exceptions. Almost all current hubs and lights are based around 6 volt, 3 watt, and can all work together. Usually the deal is your hub is going to have its own connector type which it will probably come with, like the two-...


5

Asymmetrical rims raise the weaker side tension and reduce the bracing angle disparity on wheels where the hub has a different center-to-flange distance on each side, as long as the amount of offset at the rim in question brings the dish closer to center than the offset at the hub moves it away from center. SON28 disc hubs have smaller and closer to ...


4

Uh... Surprised why nobody's mentioned: 1) A dynamo-powered light changes intensity depending on speed (may not be an issue with modern LEDs which require low power); 2) No lights at all if you're stationary. This a serious disadvantage. If you have to stop in a dark area for whatever reason (puncture, something fell off the rear carrier), being seen is ...


4

I use this product: http://www.aliexpress.com/item/Spybike-Bike-GPS-Tracker-to-spy-and-pretect-your-bike-with-ease-New-bike-tail-light/32251529357.html Since this is a tail light, it is less suspicious as a GPS tracker. You can simply charge and remove the USB cable as well. (One thing to notice since this product is not inexpensive, I epoxied the screw just ...


4

I have commuted on a Shimano Alfine 36-spoke hub for several years. I just rode a Shutter Precision 32-spoke hub 4k miles across the U.S. on a loaded bike. I have had zero problems with either wheel. You might not want to ride a 32-spoke wheel, which rules out the Shutter Precision. Based on reputation, I'm sure you would not go wrong with a SON. It is ...


4

If your rear light will not come with standlight function, so (in the options I know) the front light with standlight will not "turn it on" at the rear light. Such lamp is AXA Echo 30 Auto Steady. It has cable to connect it to the hub dynamo connector and output for the rear light. But don't get misleaded. This output only transmits current when dynamo is ...


4

You could. If you were a hobbyist, it'd be simple enough to hook a DC motor to act as a generator, smooth the output, boost-buck it to the right voltage, and use it to charge a deep-discharge lead-acid battery. From there, you could either use it to charge your USB equipment or get an inverter to run some lights. I would not hook it into your mains, the ...


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