Shimano Dynohub
Wheels & Lights

DH-3N70,3N71

Now in stock , the new Shimano DH-3N70 dynohub. It has lower drag than the NX-30, higher quality bearings (comparable to Ultegra hubs), reduced weight, and is available in both 32 and 36 hole drillings. Quick release axle only. The 3N70 does not have the very low drag of the Schmidt dynohub, but it's a big improvement over the NX-30, which I still recommend for commuters. The 3N70 is the same as the 3N71. I'm not sure why they changed the number.

The Shimano DH-3N70 dynohub will power a 6 volt headlight and taillight; any lights that meet the German requirements for 6 volt lighting systems. Available in 32 or 36 spoke with a quick release axle and skewer, $ 99.99 We also have a version for disc brake. It's available in 32 spoke drilling only. $ 99.99

You may buy just a hub, or a complete wheel built by me with the hub and a Velocity, Mavic or Sun Metal rim. See sample pricing below. call for an exact quote for the wheel of your choosing.

Drag with the DH-3N70/71 is higher than with the more expensive Schmidt hub, but less than with Shimano's less expensive Nexus NX-30 dynohub. The drag is also less than with the Busch&Müller Dymotec 6 or S6 sidewall generator when the light is turned on. Because the hub also has some residual drag even with the light off, I don't recommend it as highly as the Schmidt for timed events such as brevets or RAAM qualifiers, where the Schmidt is the obvious choice. For touring, the Dymotec sidewall dynamo might be a better choice, since in daylight, with the light off and the dynamo disengaged, there is zero drag, and most people don't tour by bicycle in winter, when snow will cause a sidewall dynamo to slip. However, even for touring, the Shimano DH-3N70 should be considered, since it has far fewer moving parts than a sidewall dynamo, making it more reliable and durable for long term use. By comparison, drag with the Schmidt hub is so low with the light off that it isn't an issue. Also, for tandems, the Schmidt would be a better choice, since it's available in 40 and 48 spoke versions.

For winter commuting, all of the hub dynamos I sell are preferable to sidewall dynamos, since they won't slip when the tire is covered in snow. And, a hub dynamo eliminates the biggest problem with sidewall dynamos: accurately aligning the roller for minimum drag.

The DH-3N70/71 hub can power either a single headlight with a 3 watt bulb, or a 2.4 watt headlight and .6 watt taillight combination.

Aside from differences in overall quality, the three dynohubs I sell also differ in performance. The Schmidt is the most efficient of the three. In other words, you do less work to power the lights with the Schmidt that with either of the Shimano hubs. This new Shimano DH-3N70/71 hub is more efficient than the less expensive Shimano NX-30. See the table below for a comparison.

Efficiency at 15 km/h,
(about 10 mph)

As you can see, the biggest performance advantage of the DH-3N70/71 over the NX-30 is in how much drag exists when you're riding with the lights off during the day. And then of course the bearing quality is much higher, since the bearings are the same as Ultegra hub bearings, rather than Shimano's low end Nexus group. The Schmidt uses sealed cartridge bearings, much like a Phil Wood hub.

I have an assortment of wheel options listed below. I have many rims to choose from by Sun, Mavic and Velocity. There is no Shimano dynohub designed for 20" wheels. You can use it, but the drag will be considerably higher, since the hub is spinning at a higher rate. For 20" wheels, the Schmidt SON 20 is a better choice, since it's designed specifically for smaller wheels and higher RPMs. Call for more wheel options.

Shipping a wheel within the lower 48 states ranges from $12 to $18 via UPS ground. Of course I can ship via air. Call for rates.

All of the headlights are available with either a 2.4 watt halogen bulb, or a 3 watt halogen bulb. If you will be using the system with a wired taillight, such as the DToplight Plus or Seculite Plus, you should use the 2.4 watt bulb in the headlight. If you'll be using the system with just a battery powered taillight, you should use the 3 watt bulb in the headlight. I stock spare bulbs; both 2.4 watt and 3 watt. Don't choose between the 2.4 watt bulb and the 3 watt bulb on the assumption that the 3 watt bulb will be noticeably brighter. It isn't. The 3 watt bulb is needed because the electronic circuitry in the headlight that prevents the bulb from blowing out when you're riding fast assumes a 3 watt draw from the dynamo. So if you use a 2.4 watt bulb in the headlight without a .6 watt taillight connected, the circuitry will not protect the bulb from excess voltage, and the bulb will burn out. First, decide whether you want to have a wired taillight, and if the wiring will not cause a problem on your bike. If you can use a wired taillight, by all means use the 2.4 watt bulb in the headlight, it will provide plenty of light. If you can't use a wired taillight, then get the 3 watt bulb in the headlight.

Grounding

Unlike the Schmidt dynohub, the Shimano hubs all ground electrically through the hub's axle. The wire connections still have both power and ground, but you must keep in mind that the axle is also grounding to the fork. A common mistake is to wire the headlight out of phase. If the headlight is attached to the frame with a metal mount, and if the light grounds to the metal mount, it won't work, since the out of phase wiring shorts with the axle grounded. Some folks have their headlight mounted with a nylon mount, so the headlight is now isolated and works fine. But if there's a taillight connected to a rear rack, it will be grounded through the rack to the frame and may not work. All of the taillights that mount on a rear rack ground through thei rmounting bolts, which enables a single wire connection.

So, you must be sure to connect the headlight to the hub with the correct connections. Connect power to power and ground to ground. Or eliminate the ground wire if you have a metal mount and a headlight that can ground through the mount. Some can but some new ones cannot, like the B&M Lumotec Fly and Fly IQ. Also remember that some headsets do not conduct electricity. Shimano cartridge bearing headsets do not conduct, so the fact that the hub grounds to the frame won't help you getting conductivity to the taillight via the frame. Use a two wire settup to be safe. But be careful about polarity. Even though the hub's output is AC, you still need to maintain polarity.

I do recommend that you use both a dynamo powered taillight and a battery powered taillight, if at all possible. If a wire should fail to the dyno powered taillight, the battery taillight makes a great backup. (We now have a very tough coaxial wire for taillights.) If your batteries fail in cold weather, the dynohub will still be working no matter how cold it is, and the taillight will be very bright. Also, all of the dynamo powered taillights have reflectors, so even if both the wiring from the dynamo and your batteries should fail, you still have the safety of a rear reflector. Redundancy is good. Redundancy is good. Redundancy is good. Stop me, please!

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 lights blowing 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. 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.

Headlights

Whatever headlight you choose, it has to have a switch, otherwise the light will be on all the time, and you'll burn out the bulb sooner. Remember, all of these headlights have overvoltage protection for the bulb built in. So you don't have to worry about riding too fast with the light(s) on. And all oif our headlights come with a bulb included. We stock spare bulbs for these headlights. LED headlights of course do not require spare bulbs.

Lumotec Oval Plus Senso headlight 2.4 watt halogen bulb (includes mounting hardware) looks identical to Lumotec Oval. The switch has three positions. On, Off, and Auto Sensing. The Auto Sensing position turns the light on when it gets dark:

An LED will light up when you stop, powered by a capacitor which is charged while you ride. The LED will stay lit for up to seven minutes.

If you won't be using a dynamo powered taillight, ask to have the bulb switched to a 3 watt version. This adds $2. to the cost.

Lumotec N Plus switched headlight. Built in slider switch. Otherwise the same as the Lumotec Plus which has the LED standlight, powered by a capacitor. Ships with a 2.4 watt bulb.

If you won't be using a dynamo powered taillight, ask to have the bulb switched to a 3 watt version. This adds $2. to the cost.

My best headlight for riding at high speeds. The Schmidt E6 has by far the best beam of any dynamo powered headlight available for high speed riding. The top of the beam is extremely bright; brighter than any other headlight that can be used with a dynamo. So when you aim the top of the beam at the horizon, you'll have more visibility at a distance than with any other light. For lower speeds, a headlight with a larger beam may be preferable, even though it's not as bright at the top of the beam. Surely, if you're commuting on fairly flat roads, one of the LED headlights such as the Inoled would be better than the E6. But when yer "comin' down the mountain", the E6 is the best! The magnetic reed switch is extremely reliable. And bulb replacement in the dark couldn't be easier. If you want the best, this is it. No mounts are included with the E6.

If you want the best of both worlds, an LED headlight for slow to moderate (under 25-30mph) speeds, and the E6 for those screaming mountain descents, the 3N70 will power two lights, just like the SON hub, a Primary and a Secondary. The Busch&Müller DLumotec Oval N as a Primary, and the E6 Secondary make a great combination. See my dynamo headlight page for more info on this and many more compatible headlights, including several LED headlights. and see this page for a complete listing of Light Mounts.

Schmidt E6 Headlight Primary 120 CM wire 2.4 watt:

Schmidt E6 Headlight Primary 120 CM wire 3 watt:

$ 109.00

$ 111.00

Taillights

I have taillights that can be powered from the dynohub, and other taillights that are powered by batteries. If you will be using a taillight powered by the hub, the headlight should have a 2.4 watt halogen bulb. If the taillight will be powered by batteries, the headlight should have a 3 watt bulb. The 3 watt bulbs are not significantly brighter than the 2.4 watt bulbs, so don't decide on a wired or battery taillight on that basis. A wired taillight wil be unaffected by cold temperature, and light will always be available. But sometimes it's inconvenient to run a wire to the rear of the bike.

All taillights use LEDs for long life and reliability. I sell no taillights with bulbs. They are not as bright as LED taillights, so why use them at all? While LEDs don't make effective headlights, since they can't be focused well, they are perfect for taillights.

Wired Taillights

DToplight Plus LED taillight for rear rack mounting,
(use with 2.4 watt Lumotec); $ 24.50

Seculite Plus LED .6 watt ligtweight taillight for mounting on fender,
(use with 2.4 watt Lumotec) Can also be mounted on a rear cantilever stud with the Cross bracket.
Seculite Plus: $ 30.00

Cross Bracket for mounting Seculite Plus on a cantilever stud: $ 4.25

4DLite Plus LED .6 watt taillight for fender mounting (use with 2.4 watt Lumotec). Has a steel bar for protection. Too heavy for mounting on a Cross Bracket. $ 36.00

You'll find more about taillights here.

Battery Powered Taillights

Spanninga LED battery powered taillight for mounting on fender, use with 3 watt headlight.
(AAA batteries not included); $ 26.00

WHAT! You don't have fenders! See my Gilles Berthoud stainless fenders.

4DToplight Permanent battery powered taillight for rear rack mounting. Two super bright LEDs in the center and one LED on each side provide a very bright light for drivers to see you by. And the large reflector area keeps you safe if the batteries fail. AA batteries not included. Use a 3 watt bulb in any of the headlights above.

4DToplight Permanent: $ 29.00

4DToplight Senso battery powered taillight is identical to the 4DToplight Permanent, but has a 3 position switch. The third position sets the light to come on automatically when it gets dark. This is a great benefit when you ride through a tunnel. Use a 3 watt bulb in the headlight.

4DToplight Senso: $ 40.00

4DToplight Senso Multi adds the ability to be powered by the dynamo hub, in addition to battery power. Use a 2.4 watt bulb in the headlight.

4DToplight Senso Multi: $ 44.00

Busch&Müller DIWA Plus system

The Distance Warning, or DIWA system for hub dynamos from Busch&Müller senses when the bike slows down quickly. When riding at night with your lights on, the taillight will glow brighter when you slow down, just like the brake lights on an automobile. In the daytime with the lights off, the taillight will come on just as a car's brake lights would. The DIWA headlight and taillight must be used as a system, though they are available separately for replacement in case of damage to one or the other. The headlight is otherwise identical to the Lumotec Oval Plus with standard Busch&Müller slider switch, and the taillight is otherwise identical to the DToplight Plus. There is no option for mounting the taillight on a fender, it's only for mounting on a rear rack, or at a seatpost binder with a special bracket we have available. The headlight uses a 2.4 watt bulb, included.

Lumotec Oval DIWA Plus headlight: $ 91.00

DToplight DIWA Plus taillight: $ 67.00

Unlike the Schmidt SON and Busch&Müller dynamos, dynamo powered lights, and battery powered lights, I do not wholesale any Shimano products, including these hubs.

See my Dymotec and Schmidt pages for my large assortment of mounting brackets and other dynamo lighting options.

Return to: Lighting Systems

Back to: Products page

Back to: Peter White Cycles home page

Mail to:

The email link above uses javascript to hide the actual address from spambots. Your browser needs to be set to run javascript in order for you to use any of the email links on my website. If you can't see the links, you can call us or send a fax. You can also type the address into your email software. First, type the alias, "pjw". Then type the "@" sign. It's above the number 2 on your keyboard. Then type the domain, "peterwhitecycles.com". Don't put in the quotes! That should do it.

We use the javascript so that the spammers can't see the actual email address. I hope it works.

Sometimes the volume of email is so great we can't get to it all. For important communication, please phone, or phax.

It's best to call before 4PM Eastern time since after that we're either running around like headless chickens or at home ready to jump into the pot.

Under no circumstances should you place an order without first reading this.

This page updated: Saturday, June 28, 2008

Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
USA
603 478 0900 Phone
603 478 0902 Phax