Basically there are two types of bike lights – lights to see by and lights that allow you to be seen.
Be seen lights
Bike lights that allow you to be seen are emergency lights for when there is sufficient light to see where you are going, e.g. if there are street lights, it is early morning/dusk, there is mist/fog, but you need something to warn other road users that you are there. These lights will not provide enough light to see by.
Even if you are not intending to ride in the dark you should have a set of emergency, be seen, lights. Fog can descend without warning on high ground, even in the summer, and if you are riding on busy roads even a little spray from wet roads can render you almost invisible.
There are a number of be seen lights available, some so small and light you will not even notice that they are there.
Lights to see by
Bike lights to see by mean just that. There are various options at a wide range of prices providing various levels of just how much you can see! As you might expect, the more you pay the brighter the light and the lower the weight (in general).
Dynamo powered – lights wired to a dynamo (powered either through your wheel hub or a friction mechanism resting against your tyre wall). These provide the convenience of instant power at anytime without having to carry batteries. You are the power source so there is a marginal amount of extra effort required (although with massive improvements in light technology, considerably less than a few years ago). The initial set up costs, especially for a hub powered system, may be higher than a battery light option.
Battery power – there are a wide range of battery powered lights that fall into two broad categories, rechargeable and non rechargeable. The benefit of a rechargeable light is that you do not have to keep buying new batteries, which can prove to be expensive. The disadvantage is that if your light runs out of power before you reach your destination you are a bit stuck (unless you have a back-up light).
I now have a Hope 1 which provides excellent light output. Level one is easily sufficient for road use and it has three more brightness levels above this. I have comfortably cycled downhill at 25mph + without fear of hitting unseen obstructions on level four. It also has a ‘be seen’ flashing mode. This is not a rechargeable light but I use rechargeable cells. I purchased 2 sets of four 3200 mAh AA cells for about £10 on-line. They seem to provide about the same running time as Lithium cells (but are cheaper per cell and can be recharged). The main down side of this particular light is that once the battery power is used up it just cuts off. There is no dimming or warning, it just stops! This can be worrying if you are doing 30mph downhill at the time. I make sure to change to a fresh set of batteries long before the current set are to expire. Two sets will get me through a [summer] night.
Timing your trip will help on your lights strategy. If you go at the end of June you will get about 16-17 hours of daylight to play with. If you try in December it will be more like 8 hours.
Do I need to take lights?
You should take emergency ‘be seen’ bike lights.
If you are planning long days in the saddle you should carry main lights in case you are delayed and have to finish in the dark.
If you are camping you could carry main lights that will double as camping lights.
If you are planning your trip in months of shorter daylight hours you should carry lights. The light levels at the beginning and end of these days can be particularly poor, especially if raining.
- Always have emergency ‘be seen’ lights attached to your bike
- Make sure your lights (inc emergency) are working before you set off on your trip. And take spare batteries/charger.
- Take a hand held torch or a head torch for reading road sign and route instructions. In an emergency the hand held torch could be zip tied to the handlebars if all other light options fail. I have a reasonably powerful led light no more than four inches long and extremely lightweight that cost less than £2 (inc batteries!) that I use for this purpose. I also use a head torch which has the advantage of pointing where you look but is a little awkward to wear with a helmet.