FAQ: Answers to frequently asked questions

What's new about the new SON models? Relative to to the 1999 model, the hub's housing is reduced in diameter and is now made completely from polished aluminum, the weight has been reduced by 40g, and the no-load (lights off) losses are slightly lower. In the (rare) situation where the SON requires maintenance, the complete internals can now be removed from the axle. Bearings, stator and connections can be replaced without having to respoke the wheel.
Does the SON fit all forks? The SON fits all "standard" bicycle forks (100mm distance between dropouts, 9mm or greater axle diameter) and feels just as much at home in shock-absorbing forks.
The wheels of folding bicycles such as the Brompton, Dahon Falträder or the new Moultons are a special case as they have narrower hubs; the SON XS has been manufactured especially for them since autumn of 2004.
Where can I look at and try the SON? Not every cycling dealer has experience with our products, but we have about a hundred regular dealers who can demonstrate the SON for you. If you find a dealer who does not carry our products but may be interested, we are glad to send documentation to them. If there no dealers in your direct area who will order a SON for you, direct orders are possible, subject to the conditions specified here.
Can disc brakes be retrofitted? No. The hub housing for the disc brake version differs in size from the standard hub housing. To change to disc brakes, you will also have to replace your existing SON with a disc brake "S" model. The disc brake SON is not approved for use on tandems. More info.
Are there color options for the new SON (either anodized or powder coatings)? Since July of 2001 the SON has been available with a black housing, using very durable CompCote anodized coating. Only the SON28 and SON28S (disc brake model) with 32 spoke holes is available with this color option.
When is there finally going to be a 12V SON? Already, new (and older-model) SONs are able to power 12V circuits at higher speed. More info.
Why does the light flicker when cycling slowly? Can't this be smoothed out with a capacitor? Because the frequency of the alternating current produced by the dynamo is dependent on speed, at low speed, and thus low frequency, it becomes particularly apparent. Above 8km/h the eye does not notice any fluctuations in the lamp's brightness. We do not regard this flickering during slow cycling as a disadvantage. Other dynamos provide a uniformly dim light in this speed range - but a flickering light of the same average power consumption is more noticable to other users of the road.
How do I build a rechargable battery lighting system which is charged from the hub dynamo? Lights with capacitor-powered LED parking light like the Lumotec Oval Plus headlight and the DToplight Plus taillight already perform this function well with minimal maintenance.
In addition, some users would like the actual headlight to fully shine while stationary or travelling slowly such as when navigating dense forest, or to partly shine to light up breakdowns on night roads, or light up a campsite or cooking area. An always-on, gearless hub dynamo offers the ideal solution for an automatically recharged stationary light system. In principle it requires, in addition to the 6 Volt rechargable battery, only a rectifier and some cable. Here are a few ideas.
I would like to power only the headlight with the SON and use a battery taillight. Is there anything I need to consider? Claw pole generators are designed to supply a maximum current at a higher number of revolutions, almost independent of the the load resistance. The SON is designed to supply a maximum of 550-590mA to the lights. In the case of using a headlight with a 6V/2.4W halogen bulb, and a 6V/0.6W taillight, this results in voltages from 6.5V to 7V.
If no taillight is attached, the voltage across the 2.4W lamp rises -- even if a regulating Zener diode is built into the headlight -- to over 7 Volts, which reduces the lifespan of the lamp substantially. During fast travel such as racing, the lifespan of the lamp can be less than 10 hours!
As this falls outside of the area covered by the German vehicle standards, we therefore recommend the use of a 6V/3W lamp in such cases, in particular the Philips type HPR64. Our new E6 headlight contains an electronic regulator, which limits the effective voltage to a maximum of 6.8V. Thus, this also allows a 2.4W headlight lamp with a failed taillight to be used for a much longer time.
The headlight seems to produce much less light after six months' use. Sometimes the LED taillight turns on only after cycling about 100m (320 ft.) The parking light does not function any longer. What's wrong? Halogen lamps "age." During the vibration caused by riding, adjacent spiral turns of the glowing hot wire of the lamp filament can become welded together. The effective length of the filament becomes shorter and the light output is reduced accordingly.
If several turns are welded together, due to the current-limiting design of the SON, the lower resistance of the aged lamp can cause the voltage of the system to drop below 4V, which can impair the function of the LED taillight as described. In extreme cases the taillight won't work at all! A quick solution is simply to replace the halogen bulb.
The lamp experiences particularly strong vibrations when installed at the front of a fork crown on shock-absorbing forks. Therefore with front suspension it is advisable to install the headlight on the handlebars or stem where it can benefit from the suspension.
Can I send a Union or Marwi WING hub dynamo to you for repair? Yes, usually. Maintenance with bearing replacement, internal corrosion removal and protection, axle play adjustment and test stand running is in most cases possible. However there are certain manufacturing defects, especially in the WING2, that cannot be repaired. Please contact us in each case before returning your WING! Usually we prefer the returned dynamo to be removed from the wheel/spokes.

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