It’s illegal to ride at night without bike lights, showing red at the rear of the bike and a white light at the front.
Before choosing your lighting system think about the type of riding you need them for, occasional rides back from the pub, serious commuting or all out off-road night riding.
Lights come in many varieties, and with modern LED technology they are very compact, lightweight and also very affordable. Many require no tools to fit and can be mounted and removed from your bike in just a few seconds. So, there is really no excuse for riding without lights. In many cases, evenings may be the only time to train and in the winter months good lighting becomes an essential training tool. Riding off road at night brings new challenges and is becoming increasingly popular, and requires very bright, high powered light outputs. Ultimately technological advances have made it possible to have high powered light output, with batteries that last for many hours, in a light unit that is both small and lightweight.
A flashing LED is extremely eye catching, helping to make a cyclist very visible. However, LED lights are predominantly for others to see you by, rather than to provide a beam of light to see where you are going, although some high powered front lights have developed the LED technology to suit this purpose too. LED lighting tends to allow a long battery life as they use relatively little power, especially in a flashing mode. Some will run continuously for many consecutive days on the same battery. LED’s are very cheap so provide cost effective way to get lights, and are also very lightweight and portable. They are a great idea as an emergency back up to high powered systems.
Dynamo lights are in the minority nowadays but they still have a place in commuting, where they can be a permanent fixture on a bike, and relieve any worries about battery life etc. Some downsides with this type of lighting are that it requires wiring which can often be the cause of faults, it’s heavier and there is often no light output when you are stationary.
Rechargeable lights have revolutionised the concept. Just like with cordless DIY power tools, battery technology such as NiMh (Nickel Metal Hydride) and LiIon (Lithium Ion) provide a long lasting and high power output from very small and lightweight battery packs. Batteries can be carried neatly on the bike, sometimes in the bottle cage, or a pouch and in some products, within the light units itself. They can be recharged in just a few hours by simply plugging into the mains, so they lend themselves well to daily use, such as in commuting. With many, many recharge cycles possible there is no need to buy replacement batteries and most systems have various settings giving you the ability to dim the light, for example in well lit areas, which gives the user some control over the expected run time.
Bulb technology has made huge leaps forwards in recent years, first with Halogen which provided a bright light, but with the tendency to be yellow in colour, and then, Halide (or Metal Halide), such as that used in high spec. car headlights, which emits a very bright light, with a blue/white colour. Halide light output is also very clean and evenly spread, so there are no dark spots and there is maximum visibility across the lit area. These bulbs are currently, top of the shop for performance, and would most likely be the choice of anyone riding regularly and fast through very dark roads, or even off road racing at night. Performance like this comes at a cost, as Halide systems are also the most expensive.
Four main battery types exist; sealed lead acid, NiCad (Nickel Cadmium), NiMH (Nickel Metal Hydride and Li-Ion (Lithium Ion). However, lead acid and NiCad are almost a thing of the past nowadays, as the technology has moved on at a fast rate of knots. For example NiCad batteries need to be fully discharged before recharging to prevent damage to the battery and allow full re-charge. This prevents 'top-up' charging. If you are riding a lot in very cold weather it is also worth noting that Lead acid and NiCad are sensitive to cold and as a result burn times may be less. So it is easy to see why NiMH batteries are the most popular choice as they are much more hardy, and easier to care for, and have twice the capacity of a NiCad.
Li-Ion are the most sophisticated - they are used in mobile phones and cameras - they weight significantly less and hold their charge for longer but they are also more expensive, however if you are using your bike lights on a daily basis their ease of use and longevity justifies the cost.
Off-Road Night Riding
If you plan to use your lights for mountain biking there are a few more points to consider than. The beam provided by your light needs to give you sufficient time to react to the terrain, so a decent beam of light is necessary to warn you of upcoming obstacles, and allow time to react. It's no good having a pool of light just in front of your wheel. The beam needs to be wide enough to take in the whole of the track and provide some peripheral visibility, and an even spread of light, without dark spots is also best. Many mountain bikers favour a head mounted light lamp as well as a bar mounted light, as this is particularly valuable in twisting single track so that you are lighting where you are looking and not where your bike is pointing. Off-road riding will subject your lamp to a large amount of vibration so it needs to be robust with a secure mounting, and in winter may also need to be weather resistant.
Points to Consider
How heavy is the battery and where on your bike does it need to go? How easy are the lights to remove and how frequently will you need to do it? How many hours of lighting will you get from one battery? Will you require a spare battery and are they available separately? Does your light system have energy saving modes? How long does the battery take to charge? Is there a helmet mount option? Are the lights waterproof?
Burn (or run) Time: How long the light will run for on a fully charged battery.
Lumens: A measure of light output or brightness that standardises the performance of various systems.
Watts: An energy rating of the bulb, but not necessarily an indication of it’s brightness.
Halide: A top of the range form of bulb technology, emitting a very bright blue/white coloured light (as used in high-spec car lights).
Halogen: A high power bulb emitting bright light.
LED: Light Emitting Diode, very efficient bulbs.
NiMh: Nickel Metal Hydride.
LiIon: Lithium Ion.
SLED: ‘Super LED’ a very high output version of an LED used to improve the amount of available light that the bulb emits.