Schmidt's Original Nabendynamo
The Schmidt Dynamo front hub or SON (Schmidt's Original Nabendynamo) is extremely reliable and has almost no drag. Made by Wilfried Schmidt Maschinenbau in Tübingen, Germany, the hub is quiet and is designed to give at least 50,000 kilometers of trouble free riding between servicings. The hub powers many different six volt headlights including Schmidt's own E6 halogen models, the Schmidt Edelux and Edelux II LED headlight, both halogen and LED headlamps (as well as taillights) made by Busch & Müller in Meinerzhagen, Germany, Supernova lights from Germany, and Spanninga lights from France.
The SON is extremely popular amongst long distance cyclists who need reliable lighting for all night cycling in any weather conditions. Brevet riders would rather have light when they need it, and don't want to carry batteries for a 1200k event. Bicycle commuters and people who don't require an automobile depend on the SON to make their cycling safe and efficient all year long in sun, rain and snow. Touring cyclists need light to make it to their next campground on a long day's trip. I use one on my mountian bike for night rides, and my road bike has one with the light switched "On" all the time.
When your bicycle can make its own light, it becomes a reliable means of transportation, not just a toy or play thing for an afternoon's entertainment or exercise. With an automobile, you take its lights for granted. You get in the car, turn on a switch, and drive on down the road with the light you need. With the SON, you can take quality lighting on your bicycle for granted, just as you do in a car, making your bicycle just as convenient to use for everyday transportation as an automobile, but without the environmental degradation. Who knows, you may even decide that you no longer require an automobile.
All versions of the hub now have a five year warrantee. Hubs sold before January 1, 2004 had a three year warrantee.
"SL" hubs use a special axle, and require a specially constructed fork to function. See all of the details on the SL hubs on this page.
All headlights we now sell with the SON hub can be used with or without a taillight. But some older headlights don't work quite as well if there is no wired taillight in the system. If you use older halogen lights or some early LED headlights, ask us about this when ordering.
We stock versions for bikes with rim brakes as well as disc brakes; both Centerlock and ISO. We have versions for folding bikes with short front hub axles, versions for 15mm thru-axle, tadpole type trikes, and even for "fat bikes" with their 135mm axles.
SONdelux Wide Body
The new SONdelux wide body gives you the lowest drag possible while also giving you the strongest wheel, due to the wide flange spacing. The standard SONdelux (see below) has flanges 50mm apart. The SONdelux wide body has the flanges 68mm apart. It's just a bit wider than the new SON28, and looks pretty much the same. Should you take a little tumble, the wider flange spacing will help the wheel resist warping due to high side loading since the wider flange spacing will maximize the lateral stability of the wheel.
SONdelux wide body, Polished, 32 hole, Part Number; SCH263208: $
If you want the lightest dynamo hub, get the 50mm standard SONdelux, below. But if you want the most stable wheel possible and don't mind the slight added weight (about 24 grams) and cost, get the 68mm SONdelux wide body. That's what I use on my road bike. I weigh 165 lbs and use the 32 hole with a Mavic Open Pro rim. The SONdelux wide body is only available in 32 and 36 hole drilling, polished, and for rim brakes only. There is no disc version, and none in black.
These are being made exclusively for the North American market, so in the center band you'll read "SONdelux wide body" and "for Peter White Cycles", since we are the North American distributor for Wilfried Schmidt Maschinenbau. But as with all Schmidt products, your local shop can order these from us.
Wilfried Schmidt has improved the SON28 for 2012.
The new for 2012 SON28 is lighter than the previous (SON28 Classic) version, has a bit less drag, and is styled much like the SONdelux. They are available in polished (as shown) Silver Anodized, Black Anodized or Red anodized; 32 and 36 hole drillings; standard connector for normal forks or SL, and three basic types: non-disc as shown above, a Centerlock disc version and a version for ISO disc, both shown below. Since the flange diameter is smaller than the current hub, 40 and 48 hole drilling isn't possible, so the SON28 Classic hub will continue to be made in 40 and 48 hole drillings, polished only.
SON28, Polished, 32 hole, Part Number SCH303201: $
New SON28 ISO Disc
Shown here, the new ISO disc version in polished finish, 32 or 36 hole. This is also available anodized Silver, Black or Red, 28, 32 or 36 hole.
SON28, ISO Disc, Polished, 32 hole, Part Number SCH313201: $
New SON28 Centerlock Disc
And the new SON28 Centerlock disc hub. Also available anodized Black, but not in Red.
SON28, Centerlock Disc, Polished, 32 hole, Part Number SCH323201: $
Centerlock Disc version is not available in Red.
Most of these new hub models are available with either the standard metric electrical connectors as shown in the top photo, or in the new SL version. See this page for details on SL hubs and forks.
The old version will from here on be called the SON28 Classic. Pricing for the new SON28 Disc hubs is the same as for the SONdelux Disc hubs.
New in 2008, the SONdelux (originally called the SON20R) is a smaller, lighter version of the SON for 16" and 20" rims. I stock it in polished aluminum, black anodized aluminum finish, and red (see below). The smaller size results in a considerable weight savings, dropping from the 570 grams of the Classic SON20 to 390 grams for the SONdelux. The SONdelux is also available for Centerlock disc brakes with either 32 or 36 spoke holes, and either polished, black or red anodized finish.
SONdelux, Polished, 20, 24, 28, 32, 36 hole: $
In January, 2010, Schmidt changed the name of the SON20R to SONdelux. Skip this paragraph if you aren't interested in German bicycle lighting regulations. ;-) The reason for the name change is a bit complicated. German law regulating bicycle lighting is very strict. A dynamo powered headlight must reach a certain brightness at a certain minimum speed. If you use a hub designed for 20" wheels to make a wheel with a 700c rim, that wheel will be rotating at a slower RPM at a given speed than the same hub in a 20" wheel, so the hub's output will be lower. With a halogen bulb headlight, the light would not reach the minimum required brightness until you were going faster than the law requires. But with LED headlights such as the Schmidt Edelux, Busch & Müller CYO and others, this isn't a problem. You can use a hub designed for 20" wheels in a 700c wheel and the light will be very bright at low speeds. Previously, it was illegal under German law for Schmidt to sell the SON20R in Germany for use in 700c wheels. But the law has been changed, provided the customer also buys a LED headlight. So now, Schmidt can sell the SON20R for use with 700c rims, as long as the wheel is used to power certain LED headlights that produce high output with very little power. So there's no longer any need to call the hub a "SON20R", implying it's only suitable for 20" and smaller wheels. Hence, the name change to SONdelux.
New in Spring, 2009, the SONdelux disc accepts Centerlock discs from Shimano. The Centerlock disc version is 32 hole only. I have these polished, black anodized, and in red anodized. The red matches the Edelux red headlight as well as the Rohloff 14 speed hub in red. See the pretty picture below. If you prefer to use ISO discs, you will need an adapter, or, use the SON 28 ISO Disc model instead.
SONdelux Disc (Centerlock) Polished, 32 hole, Part Number SCH253201: $
Some people want to use the SONdelux with 700c rims. Since this combination results in the hub spinning slower at a given speed than it was designed for, there will be slightly less drag, and the lights will reach full intensity at a higher speed. This is fine if you'll only be using modern LED headlights that reach high intensity at a very low speed. But if you ever want to use a halogen headlight, you may find the light rather dim at moderate speeds.
SONdelux SL & SL Disc
New for 2011, the SONdelux SL. This new hub makes its electrical connection through the fork dropouts, so there are no wire connections at the hub. When installing the wheel in the fork, you just pull it into the dropouts like any other wheel and tighten the skewer. That's it. No wires to connect. And no wires to disconnect when removing the wheel. You bicycle's fork must be specially made, or modified, to use the SONdelux SL hub. We have an aluminum fork from Schmidt for bikes taking 26" 559 wheels. And we have everyhing a frame builder would need to build you a fork suitable for use with the SL hub.
Click Here for all the details on the SL hub.
The new SON28 is also now available in an SL version. I have 32 and 36 hole, polished, black or red anodized, non-disc, ISO disc and Centerlock disc versions in stock.
Prices for SL hubs are now a bit lower than the standard versions, as the axle is less expensive to make, and they ship without a skewer.
SON 28 15
Many bicycles now use front hubs with 15mm thru-axles for suspension forks. This required a redesign of the SON axle and dynamo core along with larger bearings. This new version of the SON began production in October 2012, and we keep plenty on hand.
Here it is on my new IF mountain bike, summer 2013. The fork is a RockShox SID.
So if your bike has a suspension fork, or if you've always wanted a suspension fork but also wanted dynamo lighting, now you can have both. The red anodized version is a perfect color match for the Rohloff red anodized hub, as well as the Schmidt Edelux headlight in red.
Power output and efficiency is the same as with the regular SON 28.
Available in either 32 hole or 36 hole.
No Centerlock disc version will be available. ISO only.
SON 28 15, Silver Anodized, ISO disc, 32 hole, Part # SCH333291: $
SON 28 15, Black Anodized, ISO disc, 32 hole, Part # SCH333211: $
SON 28 135
For winter riding, "Fat Bikes" are the way to go. With 5" wide tires you can ride through deeper snow than with a normal mountain bike tire. But you need a wider fork. So "Fat Bikes" use a 135mm front axle and very wide rims. The SON 28 135 has a 135mm axle and the ISO disc mount is offered with two different disc spacings, for different forks.
RS 10mm is for forks designed for the rear disc spacing. FS 9mm is for forks using the traditional front disc spacing.
Rear disc spacing with 10mm axles are becoming less common, so we have these hubs at close-out pricing.
SON 28 135 RS 10mm. Black Anodized, for ISO disc, Rear Standard,32 hole, Part # SCH313218: $ 250.00
SON 28 135 RS 10mm. Silver Anodized, for ISO disc, Rear Standard, 32 hole, Part # SCH313298: $ 250.00
Front disc spacing and 9mm axles are now the most common. These are at the regular price.
SON 28 135 FS 9mm. Black Anodized, for ISO disc, Front Standard, 32 hole, Part # SCH313219: $ 431.00
Be aware! There are quite a few "standards" for front fat bike hubs. Some use a 9mm axle, some 10mm, and some use 15mm Thru-Axles. Some have 10.5mm dimension between the dropout and the disc. Some have 15.2mm dimension between the dropout and the disc. And still others use a thru-axle. So find out which standard your fork is designed to work with before ordering.
SON28 Tandem (introduced 2015)
The new version SON28, introduced in 2012, has smaller flanges that older SON28 hubs, and so only has space for up to 36 spokes. So Schmidt has now introduced the SON28 Tandem hub with larger diameter flanges, with either 40 or 48 spoke holes. We now have these in stock. Photos coming soon.
Schmidt SON28 Tandem, 40 hole, Silver Anodized, Part # SCH304092, Price: $ 296.00
Schmidt SON28 Tandem, 48 hole, Silver Anodized, Part # SCH304892, Price: $ 296.00
Schmidt SON28 Tandem, 48 hole, Black Anodized, Part # SCH304812, Price: $ 296.00
SON28 Classic (discontinued)
As of Spring 2015, we have only one SON28 Classic in 48 hole drilling, in polished finish.
SON28 Classic, Polished, 48 hole, Part # SCH6V48: $ 215.00
There are also versions of the SON for folding bikes that use narrow forks; the SON XS 28 hole for Brompton folding bikes, SON XS 28 hole for Dahon folding bikes, SON XS 28 hole for Moulton, and the 24 spoke SONXS for the Bike Friday Tikit. These folding bikes use narrower front axles than on standard bicycles. All SON hubs are designed for 6 volt headlights and taillights. These are all designed to be used with a 16" to 20" wheel.
SON XS, polished only: $ 250.00
SON XS 100
On the left is the SON XS 100. On the right, the SON XS. Inside, the two hubs are identical. The difference is in the axle. The SON XS 100 fits normal forks, the SON XS fits narrow forks on foldable bikes like the Bike Friday Tikit, Brompton, Dahon and Moulton.
SON XS 100, polished only, 24 or 28 hole: $ 250.00
The hub flanges of the SONXS100 are 40mm apart, compared with 62mm for the SON28, and 50mm for the SONdelux. The axle is the industry standard 100mm, so it fits all normal bicycles, just like the SON28 and SONdelux. The wheel will have less lateral strength than one built with the SON28 since the flanges are narrower. But consider this. Modern tandems have rear wheels with 50mm hub flange spacing, and these have now been used for many years with great success. So a front wheel with a 40mm flange width should be just fine for most cyclists. And in practice we've had no problems with wheels built with the SON XS 100. With the narrow flanges, you'll have less aerodynamic drag from the spokes, and by using the dynamo core designed for 20" wheels, you'll have less mechanical drag. Mechanical drag is lower because the hub, when used with a large diameter rim, is spinning at a slower rate than it would be with a smaller rim, at the same speed of the bicycle. The differences are small, especially since the drag of a normal wheel is already very small. But for some folks, every little bit is important.
This wheel has the SON XS 100 hub, a 32 hole Mavic Open Pro rim, light weight Wheelsmith XL14 spokes with aluminum nipples. (The SON XS 100 is no onger available in 32 hole.) The narrow flanges reduce air resistance and the hub has slightly lower drag than the regular SON28. This used to be about the lightest wheel I could build with a dynamo hub. Only changing to a Velocity Aerohead would make for a lighter wheel, by about fifteen grams. But the new SONdelux is ten grams lighter than the SON XS 100. So if you want the very lightest wheel possible, you'd use the Aerohead rim with the SONdelux, and the fewest number of spokes suitable for your weight and riding conditions. The trade-off between the two hubs is fairly simple. The SON XS 100 would ride with slightly less aerodynamic drag, and the SONdelux would have higher drag but lower weight.
Please don't ask me to decide for you! ;-)
If used with a Busch & Müller LED headlight (which use extremely bright LEDs instead of a halogen bulb) the light will reach full brightness at about 2mph! I don't recommend the use of a Secondary halogen headlight if you use the SON XS 100 hub with a 700c or 26" rim.
Got a Trike?
If you have a tadpole style tricycle, two wheels in front, one in the rear, there may be a SON to fit. Schmidt makes several versions of the SON for trikes; the SON XS-M. This hub comes with different axles for different trikes. One for the HP Velotechnik Scorpion, and one for the Anthrotech. Also for ICE and Toxy trikes. If you have a Greenspeed trike, you can ask Greenspeed to sell you a kit which allows fitting the Anthrotech version to the Greenspeed trike. For 2013, we now have a version for the Catrikes. The Catrike version is a bit more expensive since it requires additional hardware. And, since Catrike uses 28 spokes for their 16" wheels, and 32 spokes for their 20" wheels, you must order the correct drilling. We have both.
This axle fits the Scorpion. The hub is only available in black anodized finish, and with 36 spoke holes.
This axle fits the Anthrotech and Greenspeed. The hub is anodized black, the photo notwithstanding. This version comes with 32 spoke holes.
Here's the SON XS-M for Catrike. It has a couple of extra parts on the axle, which makes this version a bit more expensive.
The SON XS-M accepts an ISO disc only. There is no version for Centerlock discs. There is no drum brake version. So if your trike uses drum brakes, you must have it converted to use disc brakes. The SON replaces either one of the front hubs on a tadpole style trike. Put it on the right or the left, it makes no difference. Higher spoke counts are not necessary since these trikes use either 16" or 20" rims.
SON XS-M for Catrike, black anodized, 28 holes: $
(Don't forget to order the Adapter Kit)
We apologize for the extra cost, but the Catrike axle is unique, requiring both a pressed on bushing and a stepped washer to adapt the SON XS-M. So the SON XS-M for Catrike needs these additional parts to work. You must have the Adapter Kit for Catrike.
SON XS-M for HP Velotechnik Scorpion, 36 hole, Black: $ 417.00
SON XS-M for Anthrotech and Greenspeed, 32 hole, Polished: $
SON XS-M for ICE Trike or Toxy, 36 hole, Polished: $ 417.00
Schmidt makes wheels to replace the stock front wheel on a Brompton so you can have a quality Schmidt dynamo for not a lot of money. This new SON XS hub uses radial spokes and the same rim Brompton uses, The hubs are made in three finishes; all silver, all black, or silver sides with a black center (Silver/Black/Silver). The latter two are shown in the photo above. The spokes areall stainless steel and the rims are all silver anodized.
Schmidt Wheel, SON XS Silver hub, Brompton Silver rim, Part # SCH43110: $
Polished, Black or Red Anodized?
Most versions of the SON are made with the aluminum shell polished to a high shine. And almost all of the models are also available with the shell anodized a glossy black, or red. Some people prefer the aesthetics of one over the other. I'm solidly in the polished camp, since I like the look of old classic bikes from the 1970's. Other than aesthetics, there are only three considerations when trying to decide between polished or anodized. In some models you have no choice; only polished is offered. In some models, where there is a choice, the anodized version is more expensive. But most importantly, if you ride all year long and the roads where you ride are salted in the winter, the road salt will cause the polished surface to stain, whereas the anodized surface will remain shiny, like new.
Available now, the Edelux and most SON versions are available in anodized red to match the red Rohloff Speedhub. I have these in disc, both ISO and Centerlock, as well as for rim brake. The SONdelux disc is only made for Centerlock. And all finishes are available for the various SL versions.
The color is a perfect match, since the same German company does the anodizing for Schmidt and Rohloff. The Rohloff has more of a matt finish compared with the SONdelux, but it's still a very attractive set. We have these for both disc brakes and rim brakes. Disc version is shown here.
When these were introduced, they were only available as a set. However, we are now able to offer the light or hub by itself. See this page for pricing.
The Gizmo Factor!
In September, 2009 several companies announced chargers for battery powered "Gizmos" of the sort some people like to have on their handlebar while they ride. These include cell phones, GPS units, PDAs and the like. These chargers use the output of a dynamo hub, which would normally just power lights, and shunts some of it to charge batteries. If you intend to use one of these chargers, you should resist the temptation to use a SONdelux or SONXS100 hub with a large wheel like 26" or 700c. While you can often get away with less power running most of the new LED headlights, these chargers need the full output of a dynamo hub while you're cruising along in daylight, assuming you want to get the best performance from the charger. These chargers will be in stock starting late October or early November, from Busch & Müller, PedalPower+ and Tout Terrain. Once I have pages up for these devices, there will be links right here.
Download the Busch & Müller E-WERK manual PDF file here. 1.38mb file
Disc version on a tandem?
In the past, I didn't recommend disc versions of the SON, the SON28S and SON20S, for use on a tandem. We thought that high heat from the disc could make the hub shell too hot, damaging the magnets inside. But extensive testing has shown that the disc rotor itself fails before enough heat reaches the hub shell to damage the magnets. So we now are happy to recommend the disc version for tandem and heavily loaded touring applications. Of course, you should be careful not to overheat the discs, as a warped disc will ruin your ride. For long distance loaded touring, (tandem or single) you may want to carry one or two spare discs if you'll be riding in very hilly terrain. And, be aware that disc versions of the SON hub should only be used with forks fitted with dropouts that prevent the wheel from being removed (lawyer lips) even if the skewer is loose. Otherwise, torque from the brake can cause the hub to work its way out of the dropouts.
Crosses To Bear?
Most Schmidt hubs should not be used in a wheel with radial spoke lacing. The new SON20R can be used with radial spoking. 24 and 28 hole versions should be laced cross 2. 32 and 36 should be laced cross 3. 40 hole can be laced either cross 3 or 4. 48 should be laced cross 4. The hub axle is hollow for use with a quick release skewer. The hub ships with a 5mm hex type, skewer. Some riders will want to replace the hex skewer with a standard quick release (not included). I stock Salsa and several Mavic, Shimano and Campagnolo front quick release skewers for folks who want matching skewers front and rear when they purchase a Schmidt front wheel along with a matching rear wheel using a Shimano or Campagnolo hub. To help keep your Schmidt hub equipped wheel from being stolen, use a Pitlock skewer.
The photograph below shows the original Schmidt hub (from 1999) with one flange and the steel center of the shell removed. The newer versions are similar, but smaller and lighter.
SON28 (2012), non-disc
Flange Diameter - 54mm
SON28 Tandem (2015) non disc
Flange Diameter - 69mm
SON28 (2012) ISO Disc
Flange Diameter - Right side: 54mm, Left side: 59mm
SON28 (2012) Centerlock Disc
Flange Diameter - 54mm
SONdelux, non disc
Hub Flange Diameter - 54mm
SONdelux Centerlock Disc
Hub Flange Diameter - 54mm
Wide Body SONdelux, non disc
Hub Flange Diameter - 54mm
SON28 15 (Thru-Axle) ISO Disc
Flange Diameter - Right side: 54mm, Left side: 59mm
SON 28 135 (fat bikes) ISO Disc
Hub Flange Diameter - 58mm
Hub Flange Diameter - 70mm
SON XS-M ISO Disc (for tadpole trikes)
Hub Flange Diameter - 70mm
Hub Flange Diameter - 54mm
SON20 & SON28 Classic
Hub Flange Diameter - 70mm
SON20S & SON28S, ISO Disc
SON20S (disc) and SON28S (disc), use a spoke length 2mm shorter on the disc (left) side.
The Original SON (polished flanges, black painted center section, from 1990's)
Hub Flange Diameter - 81mm
20, 24 and 28 spokes, lace cross two.
If you wish, radial spoking is allowed on current hubs, though not on the disc versions, of course. Most older SON hubs are not suitable for radial spoking.
The SON20R / SONdelux is not available with 40 or 48 hole drilling.
Wide Body SONdelux is only available in 32 & 36 hole drilling
When building the Centerlock disc versions, since the offset to make space for the disc is so small, I find that there is no need to use different spoke lengths on the right side vs the left side. Use the same spokes all around, and you'll only have to make a small adjustment to center the rim.
The following chart shows a comparison of the various SON hub models.
Schmidt's Spoke Length Calculator
Please use this handy spoke length calculator from the Wilfried Schmidt Maschinenbau website.
SON20 & SON28 Classic Hub Alignment
Some SON dynamo hubs must be used with the connectors only on the right side of the bike. The original version of the SON28 has aluminum flanges with a black painted steel center shell. That version can be used with the connectors on either side of the bike. The later SON28, now called the SON28 Classic, SON20, and any disk version for a normal bicycle fork must have the connectors on the right side. SONXS, SONXS 100, SON20R and SONdelux can be used either way. SON20R Disc and SONdelux Disc must have their connectors on the right side.
However, the New SON28, introduced for the 2012 year can be used with connectors on either side of the frame.
Using the SON20 Classic or SON28 Classic hub with the electrical connectors on the left side of the hub can cause the internal section of the hub to unscrew from the shell, resulting in damage to the hub. This voids the warrantee. No exceptions!
I'm aware of some riders having used these hubs for several thousand miles with the connectors on the left side without incident. If the hub has been assembled with very high torque it's probably possible for it to be used this way without unthreading. But, there's no way to know if YOUR hub has been assembled with extremely high torque, and there's no way for the user to tighten the hub shell. And I'm not going to over-tighten the hub shell, since (with my arthritic back) it will only make servicing the hub more difficult should it be needed in the future. So, regardless of what you've heard about using the hub with the connectors on the left side, if your hub isn't designed for it, PLEASE DON'T DO IT!
If the hub is used backwards, the central core of the hub can unscrew from the outer shell. This can cause the hub to lock up, and it can easily damage the threads, making it impossible to reinstall the hub core. You'll be left stranded on the side of the road. This alignment is just as important as your pedal threads, which are right handed on the right pedal, and left handed on the left pedal. These threadings are different because if you had a right hand thread on your left pedal, the pedal could unthread from the crank. For exactly the same reason, the SON28 Classic hub must be used with the connectors on the right side of the bike, the same side as your derailleurs and chain.
If you have had the hub backwards in the bike, and if the hub hasn't come apart, there is absolutely no reason to suspect that any damage has been done to the hub. You have absolutely nothing to worry about. Damage can only occure AFTER the hub has come apart. Just flip the wheel around so that the electrical connectors are on the right (derailleur) side of the bike and keep on riding.
Again, if you have a non-disc SON20R, SONdelux, New SON28 or if you have a SON20M for trike, or a SONXS, or SON XS 100, you can align the hub any way you like. Of course all disc hubs must be oriented for the disc, and that puts the connectors on the right side on a normal bike.
Don't these dynamo lights Blow Up?
If you do a search on the internet for bicycle dynamo lighting systems, you will undoubtedly come across warnings about bulbs burning out if you ride your bike too fast. This is true of systems designed back in the 1920s, and used on bikes such as Raleigh three speeds up through the early 1980s. These were very crude systems by today's standards, with no voltage limiting. While you can still buy cheaply made dynamo lights that will blow bulbs on a downhill run, none of the systems I sell are so poorly made that you have to concern yourself with this. Without exception, every headlight I sell for use with either a hub dynamo or sidewall dynamo incorporates circuitry to prevent the overvoltage of the bulb. You have absolutely nothing to worry about.
The Schmidt dynohub meets the German government's StVZO regulations for bicycle lighting. Among other things, these regulations set the minimum speed at which a dynamo lighting system must provide adequate lighting. If you use the SON28 hub with a 26" or 700c rim and a headlight with a halogen bulb, you will achieve a bright light at about 5.5mph or so. Since a smaller wheel spins faster at a given speed, a different hub is used for small rims, the SONXS, or the new SONdelux. If you used a SON28 with a 20" rim, the wheel would give you full brightness at a lower speed, but would have higher drag than would be optimal. To keep drag at a minimum, the SONXS and SONdelux are designed to only give full power at a higher RPM, so that a 20" wheel will also produce a bright light at about 5.5mph.
If you use a SONdelux, designed for small rims, with large rims like 700c, and a halogen bulb headlight, the system will not achieve full brightness at 5.5mph, but instead not until about 7.5mph. This would be illegal in Germany. Hence the different versions of the SON. With some of the new LED headlights, the minimum speed for a very bright headlight is much lower. So if you know for certain that you will never use a halogen headlight, but instead only certain LED headlights, you can use the SONXS or SONdelux and have a bright headlight over a wide range of speeds.
It's a Drag, Man!
The graph below shows the efficiency advantage of current production Schmidt SON28 and SONdelux hub dynamos to current production Shimano hub dynamos. The upper group of curves shows you the mechanical power required with lights switched on. The lower group displays power required with lights turned off. Of course, the lower, the better.
One customer liked his system so much, he made a drawing. The headlight is a Schmidt E6.
Until 2005 there were only halogen bulb headlights available for the SON. We've had LED taillights, but no LED headlights until the fall, 2004 when Busch & Müller introduced the DLumotec Topal LED headlight. The halogen headlights reach almost full brightness at about 5.5mph and are very bright at 6mph. At 2mph with a halogen bulb the headlight makes a dim flicker. So I haven't suggested that people use this system for mountain biking. But with the new LED headlights from Busch & Müller the light is very bright at 1.5mph. This makes it possible to use the SON for moderate singletrack mountain biking, especially if you augment the light on the bike with a helmet light. And in fact that's what I use on my new IF mountain bike (summer 2013) using the SON 28 15 hub for 15mm thru-axles and the Schmidt Edelux headlight.
Schezbzflat! My hub feels notchy!
When you hold the wheel or hub in your hand and turn the axle, you'll feel a lot of resistance. There are 26 poles and 26 magnets in the SON28 hub (fewer in the SON20). That creates 26 points around the hub shell that the axle wants to settle in, and a corresponding 26 points where the axle doesn't want to be. In the transitions between those points, the axle wants to turn in one direction or the other, to find the point where it wants to settle. As you ride, the hub turns relative to the axle, and 26 times in each rotation of the wheel, the hub wants to turn one way, and then the other, theoretically speeding you up and slowing you down, 26 times per rotation. At speed, the effects of these two forces almost completely cancel each other out, leaving you with extremely low drag overall. It's only when you don't have a lot of mass (your weight) and inertia (your speed) that the effect is to actually retard the rotation of the hub axle. So there's no reason to be concerned about the way the axle feels when turned by hand.
The bearings cannot be adjusted!
Frequently, people decide that I'm stupid, (Who can blame them?) and that in fact the notchiness they feel while turning the axle by hand is due to the bearings being adjusted too tightly. This is not the case. There is no adjustment for the bearings! They are sealed cartridge bearings, and require no adjustment. Nor is adjustment even possible.
On the end of the axle opposite the electrical connectors of older SON hubs, the black aluminum end cap has two flats on it. Those are for use while assembling the hub in Germany, not for user adjustments. But sometimes a mechanic will hold the hub in a vise by those flats, and grab the other end of the hub axle with some pliers or vise grips, there being no flats on the connector end of the axle. This genius doesn't stop to think why there are no adjustment flats on the electrical end. The brilliant mechanical wizard then turns the electrical end of the axle, in a vain attempt to loosen the bearings. Well, all this does is break the electrical connections inside the hub, making it useless for powering a light, though it will still work just fine as a front bicycle hub. It also voids the five year warrantee. You will have to send the hub to me for a complete rebuild, (assuming you want the lights to work again) which will set you back $ 60.00 plus return shipping.
The point of this poignant little morality tale is quite simple. Leave the hub alone! If you bring your bike into your local shop for a tune-up, tell the mechanic to leave the hub alone! If the mechanic thinks he knows better than anyone else about how the axle on a SON hub should feel when turned, find yourself another bike mechanic. Only if you hear a scraping sound (an extremely rare condition which means there's corrosion on the dynamo core) while turning the axle does the hub require service. And neither you nor your local shop will be able to perform that service.
The SON has proven itself to be very reliable. Since 1998 and many thousands sold, I've had only a few dozen hubs with problems. Only two types of problem has shown up in use. First is the mechanic damaging the hub by trying to adjust the non-adjustable bearings. The other has to do with water getting into the hub, and is only a factor with older production hubs, not any that have been sold since about 2003.
As with any bicycle hub, if the wheel is kept indoors and you take the bike out to ride when it's cold and raining, the temperature of the air inside the hub will drop and the air pressure will drop. That creates a suction inside the hub that can suck water inside through the bearings. Even though the bearings are sealed this can happen. It happens on other sealed bearing hubs as well. But in the older SON, once water gets past the bearings, it can cause corrosion on the dynamo poles. As the poles corrode, the surface rust will contact the magnets (the gap between the poles and magnets is extremely small) and the hub will bind. To prevent this from happening, put the bike outside in the cold for 10 minutes or so and let the hub cool down while it's dry. Then head out into the rain. When the air inside the hub is at ambient temperature and stays there, the pressure inside the hub is constant, and no water is sucked inside.
Current production hubs (since early 2003) have an ingenious system to prevent water from getting far enough into the hub to cause corrosion. So this is an issue for older hubs, but not for any hubs you would be buying now, or might have bought since early 2003. For this system to work, there is a tiny hole in the middle of the axle. You can see it if you remove the skewer and look down the axle. And for the system to work, this little hole must be open, not clogged up with grease. So if you grease your skewers, just put a very thin layer of grease on them. Don't slather grease in a thick layer all over the skewer as it might clog up the little hole and then it's possible for water to get sucked in through the bearings, causing corrosion. So if you grease the skewer, wipe most of the grease off before putting it into the axle.
All hubs sold since Jan 1, 2004 have a five year warrantee. But if you clog the axle hole with grease, you void the warrantee!
If you need to send me your hub for service, do not cut out the spokes without checking with us first. Depending on the version SON you have, I may need the wheel intact in order to open the hub shell and work on the innards. Here are the versions.
(1) First type has polished aluminum flanges and a black steel center shell. To open this hub, the spokes must be cut.
(2) Second type has a one piece aluminum shell, either polished or black anodized. To open this type, the hub must be built into a wheel. Then a tool is attached to the electrical side and the inner core is removed by unthreading to the side with lots of torque. This cannot be done without the special tool which is not available for sale.
(3) Most of the newer additions to the SON line of dynamo hubs require cutting the spokes to open the hub for service. This includes the SONXS versions for folding bikes having narrow forks; Dahon, Moulton, Brompton, Tikit, SONXS 100 for normal forks but using thesame narrow hub shell, SON XS-M for trikes, and the SON20R. Once you are certain that any of these last types need to be opened up, you might as well cut out the spokes before shipping the hub to us since a smaller lighter box often costs less to ship.
The SON28S and SON20S (the disc versions) absolutely should not be used on a fork without a retention ridge (also called "Lawyer Lip") on each dropout. Torque from the disc brake can cause the hub to work its way out of a standard (flat) dropout during hard braking! This is a severe safety hazard! This is not unique to the disc version of the SON.
It is true of all front disc brake hubs, not just dynohubs. Any front disc hub, whether made by Schmidt, Phil Wood, Shimano, White Industries, or whatever, must only be used with dropouts having an axle retention system.
If you can remove your current front wheel by simply flipping open the quick release and letting the wheel fall out, you must not use any front disc brake on your bike!
This is not an issue with the standard (non disc brake) SON hub.
Do you like to tinker?
I'm a bicycle mechanic, who happens to import some very nice bicycle lights from Germany. I frequently get phone calls or email from people who want to try a different way of connecting their lights, often through the use of their own switch box, and they want my advice. Others want to use the output of the Schmidt hub for recharging the batteries of cell phones, Palm computers, hair dryers or Uranium PU36 Explosive Space Modulators. While I like Uranium PU36 Explosive Space Modulators as much as the next guy, I have no advice to give regarding powering one from the Schmidt. I only support using the Schmidt hub with the lights I sell, and with the wiring pattern I recommend. If you would like to try something different, be my guest. I wish you all the best, and I'm happy to sell you a hub, but you're on your own.
Wait Just a Minute!
Well, I'm still just a lowly bike mechanic. But Busch & Müller, PedalPower+ and Tout Terrain now all make chargers for battery powered "Gizmos" that people festoon all over their handlebars. These chargers take the output of the SON and will charge your "Gizmo", like a cell phone, GPS, PDA, or Uranium PU36 Explosive Space Modulator while you ride. More details as they come in.
To Switch, or Not to Switch?
I frequently get requests from folks who want to use unswitched headlights with the SON. You can use unswitched lights, but you will have to make your own switch, or else the light will be on constantly, shortening the useful life of the bulb. This is not a concern with LED headlights, which last practically forever. I do not have switches to sell. Nor can I advise you on constructing a switch. However, stores like Radio Shack sell all sorts of electrical switches and connectors. You should have no problem making yourself a switch. Be aware that the SON does not ground to the frame, unlike the Shimano dynohub and sidewall dynamos. And also be aware that the SON's output is AC, not DC. Beyond that, I don't have much to say, not because I'm not a nice guy, but because I don't know anything else! I'm just a wheel builder, not an electrical engineer. ;-)
I will point out that some people (like me) who use LED headlights leave them on all the time, since burnout of the LED isn't an issue, and having a light on during daylight does enhance your safety.
For wiring instructions, please go to the Wiring Instructions page.
For more technical information about the Schmidt hub, please read the text of Wilfried Schmidt Maschinenbau's brochure for the Schmidt's Original Nabendynamo or "SON". I've taken the liberty of editing their English translation from German to better suit the American reader.
If your German is good, you might want to see the home page of Schmidt Maschinenbau.
If you have an old Avocet cyclecomputer with the ring magnet that attaches to the front hub, you'll have interference from the SON's magnets, causing the computer to malfunction. The solution is to eliminate the Avocet ring magnet and recalibrate your computer to work directly off the SON. Divide the wheel size calibration number by 1.3 to work with the SON, rather than Avocet's ring magnet. Position the pickup next to the hub shell. Then your computer will give you correct mileage and speed.
People sometimes ask me about interference between the SON and other bicycle related electronics like heart rate monitors and the like. I don't know of any problems, but that doesn't mean there aren't any. I can't test every product out there. I only know about the Avocet issue because a friend told me about it and I'm passing along the info. I can't offer advice about other computers or heart rate monitors. But I can tell you that I've never heard of a problem.
I've had a report from one rider with a Shimano Flight Deck wireless computer getting interference from a dynamo hub. When he turns on his Lumotec light, he loses his speed readout. I haven't confirmed this, as I don't use any cycling computer myself. But if you have a choice, you may be better off using a wired computer.
We have quite a few taillights that can be attached to the headlight. If you use a taillight with a halogen headlight, you should use a different bulb than if you use the headlight alone. With an LED headlight, there's nothing to change in the headlight regardless of whether a taillight is used.
The Great Taillight Controversy
Some people worry that if they have a taillight wired to the system, the wire might be damaged somehow, causing the taillight to fail. Others take their bikes on trips via airplane, and need to remove rear racks and fenders to pack the bike, and the dynamo powered taillights need to mount on either a rack or a fender, raising the issue of having to disconnect a wire along with the rack or fender.
But these issues need not be a problem. I have plenty of wire connectors here that can be used in-line, so that when you remove your rack, you quickly disconnect the wire right along with it. I get them from Radio Shack, and so can you, but I'm happy to give you some. Unbolting a rack is a lot more work than disconnecting an electrical connector that's designed for that purpose. And by using dynamo powered taillights, you reduce the need for batteries, the expense of buying new ones, and the hassle of being sure rechargeables are properly charged. Battery taillights are great for backing up dynamo taillights, in the rare case of a wire failure or circuit failure inside the light itself.
As of March 2007 I also have heavy duty coaxial wire available which should make people less concerned about wire failures. In practice, wire failures are extremely rare, even with the light weight wire from Busch & Müller. I know this because I have quite a few customers for whom I have installed their taillights myself, and who ride many thousands of miles a year, and are here with their bike quite frequently. It just isn't a problem, in practice. I sell several hundred wired taillights a year, and it's rare to have a customer call to complain about his wire failing. Almost all calls come while the customer is installing the system for the first time. I still recommend a second battery powered taillight, either for the added light, but mostly as a backup in the rare event a wire does fail. However, it's generally best to leave them switched off, and save the battery for when it's really needed on a rainy night. When you consider all of the pros and cons, if you could only have one taillight, if at all possible it should be wired and powered by the dynamo.
Charging Batteries with the SON
There is a way to charge AA NiMH batteries with the SON dynohub. Busch & Müller makes the Ixon and Ixon IQ headlights, which are battery powered. They also make the Ride & Charge, which is connected between the SON and the Ixon. Read all about it here.
Click here for light mounting options.
Click here for wiring instructions.
Your SON hub equipped wheel is expensive. You can help keep it from being stolen from your bike by using a Pitlock skewer.
Where Can I Buy One?
You can buy one from us. Just give us a call at (603) 478-0900
Or, since Peter White Cycles is the distributor for Schmidt throughout the US and Canada, you may be able to order from your local bicycle shop. See below.
Shop List by State/Province
If you live outside the US or Canada, please first check this web page to see if there is a distributor for Schmidt products in your country. http://www.nabendynamo.de/kauf/international.html
If there is, I will not ship any Schmidt products to you. You must contact the importer in your country.
Dealer Inquiries Invited. Please call 603 478 0900
If you have a retail bicycle shop, or are a bicycle manufacturer or professional wheel builder, you can purchase the SON hubs and lights, or built wheels for resale. Any shop in the US or Canada can purchase SON hubs and lights for sale in your store. Please call me for wholesale pricing on hubs, lights and complete built wheels with Wheelsmith spokes and Velocity rims built by Peter Jon White. Peter White Cycles is the official representative for Wilfried Schmidt Maschinenbau in the US and Canada, and we want all bicycle shops to be able to sell the SON. But, we will absolutely not sell any Schmidt products to bicycle shops outside the US or Canada.
For more information, see my dealer page.
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This page updated: Friday, May 1, 2015
Peter White Cycles