The dynamo hub has made a resurgence over the past decade. For those unfamiliar, a dynamo hub is a hub that uses a small internal generator to produce electricity as the bicycle wheel rotates. This electricity powers a light system and can charge a small electronic device with the right setup. Advances in magnet technology and the rise of efficient LED bulbs have made dynamo hubs smaller, lighter and more effective than ever before. Quality hubs are being made by Schmidt, Shimano, Shutter Precision, and others. If you’ve been considering a dynamo system, there’s never been a better time.

The three types of riders that most often use dynamo hubs are daily commuters, riders that do multi-day bike touring, and long distance Randonneur riders. For the commuter, dynamos provide a near maintenance free lighting system that they don’t have to think about. It’s just always there, never needing charging or fresh batteries. You can grab your bike and go with one less thing to worry about. Touring riders use their dynamos as a charging station that keeps their devices charged no matter how many days they’re on tour. Very handy when you’re using GPS as your guide or your phone is your only connection to civilization. Randonneurs can’t afford to have a light battery die in the middle of a 1200km ride so the dynamo hub system gives them a reliable, battery-free system they can depend on for the long haul.

There are some trade-offs for all of this convenience and reliability. Cost is one factor. The high end systems can be quite expensive, but there are entry level hubs and lights available as well. You must have a dedicated wheel built for the dynamo hub itself, then lights and wiring must be installed. While not terribly difficult, setting up the system can be time consuming. Adding a USB charger into the mix can add cost and complexity, depending on how you choose to do it. The good news is that you only have to do it once. There’s also a bit of a weight penalty, since dynamo hubs are heavier than a standard front hub. The dynamo magnets also produce a slight amount of drag when rolling, The amount of which depends on the hub and whether the light is turned on. For example, the Shimano Alfine dynamo requires 2.2 watts of additional force at 30 kph, while the Schmidt requires 1.2 watts at the same speed. That is with the light or charger turned off. Both hubs require between 6 and 7 watts when the light or charger is switched on at that speed.

Modern dynamo hubs are meant to be mostly maintenance free. Manufacturers require the hubs to be serviced by professionals and hubs must be shipped to service centers. Attempting to service any dynamo hub yourself is a dicey affair. Most require proprietary tools and also have delicate electronic parts that are easily damaged by inexperienced hands. This is where the longevity of a hub comes into play. As a general rule, the higher end hubs can travel farther before problems occur. Schmidt, for example, says you should get tens of thousands of kilometers out of one of their hubs before any maintenance is required.

Much of the best bicycle lighting available comes from dynamo specific lights. Companies like Busch+Mueller, Schmidt, Supernova, and Herrmans have headlights that provide wide, evenly illuminated light fields that cover a large swath of the road ahead while not blinding oncoming riders. Compared to the focused round beams of most battery powered lights, it’s almost no contest when it comes to road visibility. You can see some nice beam comparisons here.

This is just an introduction to dynamo systems. If they interest you, we’d love to help you put a system together. Our expert mechanics can have you up and running in no time. Whether you want a reliable lighting setup, or a full charging system, we can help you select what will fit your needs best.

For further reading we recommend the following pages:

Here’s a Rodriguez with a Schmidt hub and light system

Peter White’s page is a deep well of information on dynamo systems

Cycling About has some good info about chargers

Sheldon Brown has some dynamo history

Jan Heine’s blog has lots of different posts on this subject (mostly Schmidt-centric)