Aguste de Méritens' lighthouse generator
Source: Wikimedia Commons. Scan from: Kennedy, Rakin (1903 edition (five volumes) of pre-1903 four volume edition.) Electrical Installations (Vol. IIIed.), London: Caxton, pp. p. 205, fig. 198.
A dynamo is a device that converts mechanical into electrical energy. One use of dynamos is for powering bicycle lighting systems. Whereas older or cheaper dynamo lighting systems often involved a roller device driven by a tire or rim, modern dynamo lighting systems have the dynamo inside the hubs (hence "hub dynamos" or “dynohubs”). This significantly reduces friction generated by the dynamos as well as eliminates tire- and rim-wear.

What Canadians call a "gasbar", with attendand convenience store

Source: Wikimedia Commons. Photo by: Trekfilier.

Unlike battery based lights, dynohub based lighting systems are normally fixed to the bicycle like other components and are thus not easily removable without tools. It is also possible to enhance the security of these systems by using uncommon fasteners to further reduce theft and vandalism.

Most cyclists that have tried a modern hub dynamo lighting system would never consider going back to battery lights. Commonly cited benefits include:
  • Unlike battery based lights, you no longer need to mount and then remove lights every time you ride.
  • Because the lighting system is powered by a generator housed within the hub of the wheel, users never need to recharge the system or worry about dead batteries.
  • Having a dynohub is like having a battery that is always fully charged "as if by magic".
  • Dynohubs are also among the most dependable bicycle components available. They are maintenance free except for that required by regular hubs and have well over half-a-century of field and market testing behind them.
  • You no longer need to “plan” your cycling around recharging your bicycle lights in addition to all the other electronic gadgets you likely have.
  • Indeed, you no longer need to think about lighting at all and can dedicate those neurons and synapses to other more productive uses.
  • You no longer need to worry about forgetting your bicycle light and finding yourself riding in the dark.
  • You are thus safer, more conscious of your surroundings and have nothing further to do after an initial set up.
Properly fitted, mid- to high-end dynamo lighting systems like those we carry will provide more than sufficient lighting for riding at high speeds in pitch black conditions for years without any form of subsequent maintenance!


Design for a sustainable living space
Source: Wikimedia Commons. Design by: Kyle Butler.
Although rechargeable bicycle lighting systems are more environmentally friendly than ones based on disposable batteries, even the best of rechargeable batteries eventually wear out and contribute to our global stock of chemical waste. Moreover, drawing power from the grid to recharge batteries  however little  is also part of the problem, particularly when more convenient and effective alternatives exist. The generator not only eliminates the need for batteries and ensures that the lighting system is powered whenever the bicycle is in motion … but why stop there?

Optional accessories allow the cyclist to store power generated by the dynohub to a USB powerbank (yes there is a "slight" contradiction here), that can in turn recharge most USB standard devices such as mobile phones, smartphones and GPS units.

Why add a powerbank? By allowing surplus energy to be stored, whether by fast riding or when not powering the lights or USB devices, cyclists are then able to substitute human effort for applications that would otherwise tax the power grid. The ability to store power also allows for a number of safety supporting advantages particularly when bicycle touring.

A cyclist could for instance ride with lights off during the day thereby charging the powerbank to ensure sufficient power for riding with lights on and GPS running at night for a prolonged period. The cyclist may also remove a powerbank from a bicycle to charge it from the USB port of a computer to provide supplemental power for electronic devices when planning longer night rides.

And, who knows, you might one day even be plugging your "human" power back into the power grid.


Advertisement for a Cogent Safety Bicycle, Barkers Wolverhampton Trade Directory, 1887
Source: Wikimedia Commons. Author: H. Clark.

Bicycle safety studies regularly confirm that on average 95 percent of bicycle trips occur during the day, and roughly 50 percent of bicycle accidents occur and night. This equates to the fact that the very small percentage of nighttime bicycle trips are the source of half of all bicycle accidents. Who has not ridden home at night without lights − including those who have already purchased battery powered ones?

Safety is both the overarching and primary reason behind IDC's development of its product line. Its genesis had its roots in the conviction of IDC's founder that commonly available hub dynamo lighting systems were either cost prohibitive or too complex or both. Once confined to a small circle of enthusiasts with time, expertise and discretionary income to purchase and install them, the founder wanted to develop dynamo lighting systems technically comparable if not superior to existing ones, but that are nevertheless financially and technically accessible to a broad public. Ideally, the benefits of dynamo lighting systems should be a realistic option for parents to install on their children’s bicycles.


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Marcel Fontaine
Dec 30 2014

With USB charged light ,when we are finish cycling do we still have light for a while since there is no battery?if I want to mount my tent in the dark? So would it be wiser to have light with battery charged with USB device?

Fjord Jordaan
Mar 24 2016

Hi. The bearings on my hub must be replaced. Could you send me technical information on how to replace the bearings? Or could you refer me to a company in South Africa that could assist me? Your assistance is appreciated. Fjord Jordaan

IDC Staff
May 07 2016

Hi Marcel, you certainly have a point that with a USB light you are able to set up a tent after you stop riding. Of course you would also need to pay attention to the logistics involved in keeping it charged. My preference is to use the Revolution ( to charge a USB light or powerbank while riding which makes for more self-contained riding . Hi Fjord, SP hub dynamos are not user serviceable and any attempt to do so would void the warranty. Currently your only option is to send the hub back to SP for new bearings ( If you purchased the hub from Intelligent Designed Cycles and are within the two-year warranty period, we will cover shipment of the hub back to us take care of the service and ship you the replacement free of charge. Just contact us via email.

Feb 04 2021

Hi there, I would fully concur with all the comments in the article, Dynamo lights are a no brainer, how many times have we been out longer than anticipated, or a sudden storm/fog has made riding without lights really dangerous. Living in the UK, this happens all too often. Fifteen years ago, I used to go out night cycling with a group of friends, one of whom had a dynamo, within a year, we were converted, and all had them! I tour in France most years with camping gear, and use the hub dynamo to charge power banks for mobile phone etc. (having said that, a small Anker solar panel does in an hour what the dynamo takes 50 miles to achieve, that's in the South of France, different story in the gloomy UK!) I have front and rear (now sadly defunct) Phillips Saferide lights which are truly amazing, brilliant, every pun intended! I'm sure the Axendo 60 with its similar design but with daylight running lights is even better. I've fitted an SP hub to my road bike, which is almost un-noticeable, both visually and in terms of riding performance yet gives me the same degree of safety, day and night. Fit and Forget, dynamos are the way forward, why we see so few in the UK, I don't know, visit Holland and Germany and they're more or less standard. As for putting the tent up in the dark, which often happens, I always carry a USB powered head torch, which doubles as an interior tent light, and never runs out of power because the dynamo replenishes it. All I would say to those who are skeptical, if you can, borrow a bike and try for yourself, you won't regret it. Thanks for the great article.

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