Dynamo sleeve – what it is, example of use

The bicycle, despite its 200-year history, is still one of the most popular forms of transport. Everyone – from the youngest to the oldest – rides one. There is nothing to be offended by, the experience of riding a bicycle can not be compared with the experience of a car or motorcycle. The world does not stand still, and the emergence of new gadgets makes the manufacturers of various accessories for bicycles “move”.

One of these is a hub dynamo. Tiny, but quite tangible in weight detail, which will allow the cyclist to stay in touch even where there are no wolves.

What is dynamo-hub


The principle of action of the discussed accessory is explained by Faraday’s law of electromagnetic induction. We must have:

  • a magnetic field;
  • a frame of wire in the same magnetic field.

If the field or the frame itself is set in motion, an electromotive force will appear in the wire from which the latter is made. If you connect a load to the wire (light bulb, headlamp or resistor) – everything will light up and work. A manual dynamo works if you twist it with your hands. Agree, this is uncomfortable and impractical – the time spent spinning can be spent much more interesting.

But the hub dynamo is one of the best devices for a bicycle. You have to pedal in order to ride. So why not put that energy into another direction? Like partially turning it into an electrical charge for gadgets.

What you need it for?

A compact device solves several problems. With the help of the hub dynamo you can charge your smartphone, connect a headlamp or flashlight and enjoy night drives (not safe, but interesting). It’s definitely a must-have for those who:

  • Rides often and for long periods of time away from civilization, where there is no way to connect to the grid;
  • Tired of constantly thinking about recharging a headlamp or flashlight.

Read also Stop light on a bicycle – what is it, how to make your own hands


Many people will think that the poverbank in this regard is much more reliable and practical. But this is not true. First, its charge is not eternal, and in order to power it, you will still have to look for a socket. Secondly, cyclists do not like complications, and with the battery on the road anything can happen. It can get wet, land badly, or the seat can get clogged with debris.

The dynamo has a number of advantages over similar power sources.

Advantages of using it

advantage of dynamo bushings

The first and most important advantage is that it always works when the pedals are turning. There are other advantages:

  • small size (it will not take up much space among the rest of your luggage);
  • it is not afraid of vibrations (you can safely drive on gravel roads without fearing for the device);
  • it works equally well in rain, snow, or 30-degree heat;
  • there’s no need to look for a power outlet.

The dynamo allows you to stay connected in places where a solar panel or PowerBank might fail. Which means the compact device is sure to be useful for those who like to take long walks and multi-day trips.


There is nothing without them, because in our world nothing is perfect. As for the specifics of using the hub dynamo, then surely many may wonder about this point: how much harder it becomes to pedal in the presence of the discussed accessory?

This question has been studied repeatedly by engineers and manufacturers. As practice shows, there is still resistance, but it is minimal. Nevertheless, there are several nuances that leave stains on the impeccable reputation of the dynamo hub:

  • You can’t charge your smartphone directly from the hub dynamo – you need an adapter or, as it’s properly called, a converter.
  • The hub dynamo delivers alternating current, not direct current. And the headlamp, for example, needs the latter type of power. You will either have to buy a special headlamp, or buy an additional converter for the hub dynamo.
  • The power output depends directly on the rotation of the pedals. You have stopped – the headlight went out (if low-quality – immediately, if high-quality – will work 5 minutes more).
  • In addition to the hub dynamo you should buy an extra battery which will accumulate energy and give it out when the hub is running at low speed or not running at all.

Read also Bike handlebar stem – design, how to choose


And a couple more nuances, which should have warned potential owners of the compact device. In order not to simply burn out at high speed, the headlamp or converter must have protection from high voltage. Some modern models of dynamos already have built-in overload protection. This also applies to buffer batteries – they often come with the hub as well.

Example of use

dynamo bushing explosion diagram

As we have already said, the hub dynamo is a very useful thing on the road. With its help, you can recharge a dead phone, navigator, camera and many other devices. It does not produce a direct current, and the amount of energy produced depends on several factors:

  1. the model of the hub;
  2. the device that’s connected to it;
  3. the circumference of the wheel;
  4. speed of rotation.

Experts estimate that a hub dynamo consumes approximately 3-5% of the pedal energy to operate. These figures depend on the road. It is clear that it is already difficult to understand Uphill—how-to-learn–tips, and if another 5% of effort will go to the work of the hub, it is generally sad. At the same time, you can simply disconnect the device when climbing.

Selection Tips

Before deciding on a choice, you need to decide what purpose the device will be used for. It is clear that from time to time from the dynamo hub will also work the headlamp. This only means that the two devices must fit together. Otherwise you will have to buy several converters.

To put it crudely, buying just one dynamo hub is a very dubious proposition. You should think about a set. Then we should think about what tasks the device should perform – only to light the way or to charge the device?

When choosing a particular dynamo hub, you should pay attention to several parameters:

  • power factor;
  • compatibility with other devices;
  • construction reliability;
  • availability of a buffer battery.

There are standard hub dynamos on sale, and there are specific devices (from Shimano, for example) that allow you to solve only a few problems. Accordingly, and should be guided by a clearly defined task for the hub dynamo.


The compact device in question increases the level of comfort for the cyclist. It is clear that the dynamo hub is not necessary for every bike owner. But this small device is just necessary for those who like to spend a lot of time on the road.

Read also Bicycle chain – marking, parameters


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Comments: 2
  1. Joy Mendez

    This is a great post about dynamo sleeves! It provides a clear explanation of what they are, as well as an example of how to use them. It’s very informative and i learned a lot from reading it. Thanks for the helpful information!

  2. Donna Townsend

    Great article! I found it really informative and helpful in understanding what a dynamo sleeve is and how it can be used. Thanks for sharing your knowledge!

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