In this article, we’ve gathered together some advice to help you buy a bike light.
There are three main types of lights available:
The headlight: A headlight is a front-mounted lamp which projects a beam forwards, (funny that), making the road visible at speed when cycling.
Visibility light: These lights are front or rear and are primarily designed to make the road cyclist visible, particularly in urban traffic environments.
Mountain bike light: Off-road lights are very powerful front-mounted units. These are the most advanced and brightest of all lighting systems and can also be used as very good road commuting lights.
Before choosing a light consider your local conditions, e.g. how much ambient or street light is available? From this you can figure out how much light you will need, and whether a headlight or just a visibility light will be necessary.
Bike Light Brightness
Watts or Lumens? The first important consideration is brightness. All modern lights use LED (light emitting diode) bulbs, and there is a range of levels of quality among LED’s. Generally speaking, you get what you pay for.
When purchasing a flashing visibility light, the brightness is fairly standard among different bike lights, although some better models feature a super bright LED bulb. This is ideal for maximum visibility on a rear light and can be quite dazzling to look at directly.
Likewise on the front, if you want to see where you are going a 1 or 2 watt LED bulb is ideal, anything less is really just a light to enhance your visibility to others, but not to illuminate a path or road.
Brightness Measurement: The lumen is the derived unit of luminous flux and is the measure of visible light emitted by a source. Luminous flux measures wavelengths visible to the human eye and are different to radiant flux (power) as this is a measure of all electromagnetic radiation emitted. A lux is one lumen per square meter. Basically, more lumens means more brightness.
For high end commuting or mountain bike lights, you’ll notice the use of “lumens” in the product description. Good bike lights can be rated at around 250 lumens or higher, while on upper-end mountain bike lights you will see lumens figures in excess of 1000-1200. As a guide, this is approximately as bright as a car headlight!
Mountain bike lights are so bright because of the nature of riding off-road at speed. You need to easily see what’s ahead of you. This also translates to the road. If you ride at a very fast speed a good set of lights is important, and will help you quickly spot obstacles such as pot holes.
Bicycle Light Battery
Batteries improve as brightness intensity goes up. On basic flashing “be seen” lights you’ll typically find lithium watch batteries and around 100 hours of run time. It then steps up to AA or AAA batteries in the 1-2 watt or multi LED headlights and an approximate 24hr run time on full beam, or much longer in flashing mode.
For a regular night commuter, lights using these battery types are probably not going to be ideal.
High powered commuting and mountain bike lights often use a separate lithium-ion or lithium polymer rechargeable battery pack. Even on the most powerful 1000 lumen lights, run-times of many hours are often achievable before charging is necessary.
For mountain bike lights the battery is sometimes as important as the light unit itself. There are many seemingly very inexpensive, yet super bright lights available, but some products are cheap for a good reason. The bulbs can be ok but you risk having the battery fail mid ride.
Bike Light Useability
Bicycle lights are designed to be bright and compact. One thing to look for is an appropriate and easily set up bracket for attaching the light to your handlebars, seatpost, backpack or helmet.
For road commuting a handlebar mounted front light, combined with a seat post mounted or helmet mounted tail light is ideal.
When mountain biking the best setups feature a helmet and handlebar mounted front light.
When commuting I it can be a good idea to use as many rear lights on as possible. Try one on your helmet, backpack and seatpost. Multiple lights will make you even more visible.
Buy the best lights you can afford. As mentioned earlier, LED bulbs are not all the same quality so get the best you can. Brightness levels can vary by a huge amount as you get better and better LED’s. Spend wisely, particularly if you commute regularly or want to ride in the forest on a mountain bike in the middle of the night.
Also, light casings and mounting brackets are very different as the price goes up. Again, durability can make the purchase of a slightly more expensive set of lights the most cost effective choice in the long run.