The Essential Guide to Dynamo Hubs

By Rob Savin

Putting a dynamo hub on your bike means you can power lights and charge your electronics wherever you go. Power is always with you!

Dynamo hubs are brilliant for multi-day bike touring, endurance racing and daily commuters looking for maintenance-free riding.

What is a Dynamo Hub?

A dynamo hub is a hub that produces electricity when the front wheel turns. It uses a small internal generator that works by passing powerful magnets over a coil. A wire connects the hub to whatever it is you want to power. It's as simple as that!

5 Reasons to get a Dynamo hub

  1. Power is always with you. As long as your wheels are turning, you'll never run out of electricity. So you can go further and carry less weight in spare batteries.
  2. Dynamo lights are really bright and give a very even lighting pattern.
  3. Dynamos can charge batteries, phones, GPS devices and e-readers. In fact, they can charge most small electronic devices.
  4. Dynamos work great in wet and humid conditions across a wide range of temperatures.
  5. Your bike is always ready. No need to charge your lights before you go out!
Dynamo Hubs

What can you power with a dynamo hub?

Dynamo hubs can power lights, batteries and small electronic devices like phones, GPS and e-readers.

Dynamo lights

Dynamos can power front and rear lights. Super-bright and efficient LED bulbs mean that modern dynamo lights are exceptional. They produce very broad and consistent lighting patterns to light the way. In fact, compared to the standard circular beams produced by battery-powered lights, a dynamo light can give a much broader pattern on the road or trail in front of you. Many are so bright that the beam pattern is altered similar to a dipped headlight to make them road-legal in Germany!

Don't worry, dynamo lights won't go off when you stop moving. Most dynamo lights have a "stand light" function that means they will stay lit for around 10 minutes after you stop moving. So a stop at a set of traffic lights is no problem.

Charging batteries and electronic devices with a dynamo

To charge batteries and electronic devices with a dynamo hub you need to use a power converter. This converts the AC power from the hub to DC power and stabalises the current from the hub to protect your device. They're simple to set up and there are some neat solutions, like the Cinq Plug III.

How fast do I need to ride to product power from a dynamo?

As a general rule, any speed over 10kph or 6mph will produce power for lights and batteries. Of course the, faster you go, the more power you produce, up to around 25kph or 15mph. At this point, you've reached maximum efficiency. You can go faster, of course - it just won't produce any more power. Bad news for us hoping Chris Hoy might be able to power our washing machines!

Do dynamo hubs slow you down?

Dynamo hubs have a very small effect on your speed. But it is very small. It depends on what you're using your dynamo to power too. Here are a couple of ways to show the effect a dynamo has.

The effect of a dynamo on the time to ride 100km

Compared to a standard hub, a dynamo hub would add around 30 seconds to the time it would take the average person to ride 100km. This is without the dynamo charging anything. If you rode 100km using a dynamo to power your lights and charge your batteries/phone/gps, it would take an around 4 minutes longer than if you were using a standard hub.

The effect of a dynamo on speed in relation to the power of a rider

For an 80kg rider with 15kg of bike & gear, riding at 150W the speeds on a flat road with different hubs are as follows.

  • Standard hub: 28kph
  • Dynamo hub powering nothing: 27.9kph
  • Dynamo hub powering lights and batteries: 27.5kph

So there it is! Everything you need to know to help you decide whether to go dynamo. Once you do, you'll never look back!

Super Nova E3 Triple

Supernova E3 Triple 2
Powerful 500 lumen dynamo light designed specifically for racing with three speed-controlled high-performance LEDs

LoveMud Juice Dynamo Hub

Love Mud Juice
Super smooth 6V/3W dynamo disc hub for running your lights and recharging your batteries on the move

Cinq Plug III

Cinq The Plug III
Dynamo-powered charging unit which converts AC power into DC, charging devices at speeds over 12km/h via a USB top cap

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