Understanding Bike Lights

Bike lights are essential when cycling in the city at night or in limited visibility.

There are lots of different types of bike light available, ranging from cheap battery-powered clip-on lights costing a few euros through to expensive high-intensity lights that can cost €500 – and the lights you’ll need depend mostly on the type of riding you do.

Battery-Powered Lights

Battery Powered Lights
Battery Powered Lights

For most city riding, battery-powered LED lights are normally sufficient. With good street lighting available, your bike lights are not there to light up the road – they are there to make you visible to other road users.

These type of lights usually have two modes – constantly-on and flashing. When constantly on, it’s easier for other traffic to judge your distance, direction and speed, but will also wear down the batteries more quickly. When flashing, the lights are more likely to grab the attention of others, and will more readily identify you as being a cyclist.

LED lights have the advantage of being light and relatively cheap. They come with plastic clips that can be used attach them to handlebars and seat posts – and sometimes to clothing and helmets. Most will also un-clip, so you can take them with you when you park your bike – which can be useful, as for some reason bike lights attract thieving fingers!

Rechargeable Lights

Rechargeable Light
Rechargeable Light

If you get fed up of constantly changing batteries then rechargeable lights may be for you. They are usually more expensive than battery-powered lights, but have the advantage of being rechargeable!

Rechargeable lights tend to be brighter than battery-powered lights, and are often used by people who need to illuminate the road, as well as make themselves seen. With these lights, the “power” of the light is often measured in lumens – the more lumens, the brighter the light.

The very brightest and most expensive ones often come with separate battery packs, as they will use quite a lot of power. But the more modest rechargeables will often be indistinguishable from the battery-powered lights.

Dynamo Lights

Some bikes – notably ‘dutch’ style bikes or ‘city’ bikes – come with dynamo powered lights. They are powered by the turning of the wheels, and therefore don’t need batteries or recharging.

Dynamo Light
Dynamo Light

Dynamo powered lights are sometimes viewed negatively by people who remember the old direct-contact dynamos that grip against your tyres. These types of dynamo can be inefficient, and don’t provide much light for the effort involved – and more importantly, go dark when you stop moving.

However, dynamos have moved on, and most there are many designs out there that don’t place any drag on the wheels, and also keep going for a couple of minutes when you stop.

Hub Dynamo
Hub Dynamo

You can get hub dynamos that are highly efficient, and are built into the hub of your wheel. They suffer from none of the problems of the direct-contact tyre dynamos – and most people wouldn’t even notice them in operation.

On my bike I have a Reelight attached to my back wheel. It’s  powered by a process of electro-magnetic induction from some magnets attached to the wheel passing over a coil attached to the frame. There’s no friction and no noise, and it’s great to have as an always-on backup light for when I forget to bring my lights or the batteries have run out.

Selecting the right lights for you

As with so many things in life, you get what you pay for. And some cheap lights from the supermarket are not going to be as good as expensive ones from a specialist bike store. Having said that, developments in LED technology over the last few years have helped improve the quality of cheaper lights.

I’ve also noticed a general increase in the brightness of bike lights being used in the city. And while this can help make sure you’re seen by others on the road, there’s sometimes a fine line between increased safety and being antisocial. Very bright lights, designed for use on unlit roads or countryside trails, can often dazzle other road users.

Whichever lights you use, it’s good advice to keep them charged up at all times, or to carry spare batteries with you. After all, you don’t want some last-minute changes to your plans (or the weather) to catch you out!

For more information see also:

Richard Bloomfield

Richard is the founder of Dublin Bike Blog. He commutes to work every day by bike, come rain or shine, on his Dutch city bike. You can read more from Richard on his blog richardbloomfield.ie.

3 thoughts on “Understanding Bike Lights

  • 15 June, 2016 at 8:24 pm

    Hello I would like to bey a dinmo set for my bike how can I get this iron from you and how much is it .

    • 15 June, 2016 at 9:23 pm

      Hi how can I get a dinamo kit from you and how much is it . Thank You .

  • 15 June, 2016 at 9:26 pm

    Hi how can I get a dino kit from you and how much is it .Thank You.


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