There are two main types of light - lights to see by and lights to be seen by. Lights let you see the road ahead, and lights also let other road users see you. You also need to have lighting that announces that you're a cyclist. At night it is much more difficult to estimate speed. You need to have lighting that makes you look like a cyclist to help other road users estimate your speed better.
The law in the U.K. states that during the hours of darkness you must use a British Standards approved light on the front and rear of the bicycle. The bike should also be fitted with reflectors showing to front and rear, with additional reflectors on the wheels and pedals. Flashing lights are reserved for specific vehicle groups, and so you're not allowed to have flashing lights fitted to the bicycle, although it's perfectly permissible to have them fitted to the rider. The British standard also requires that the bulb be of the 'filament' type, presumably a throwback to try and stop the use of acetelyn lamps. However, the Standards have yet to catch up with the technology, and having a LED light as your only light is not legal. LEDs can be far brighter than filament bulbs though and the local Constabulary usually turn a blind eye to LED-only use. I've occasionally heard of people being threatened with prosecution for illegal lighting, but never heard of a case going ahead. YMMV.
Reflectors are often the first thing that the bike loses, usually the moment the riders leaves the shop. Some reflectors are useless and I'm not surprised they get binned at the first opportunity. Reflectors maybe look a bit naff too, especially if they're on a race bike. Reflectors do serve a purpose though, and I'd think twice before removing all reflectors. On my recumbent, the front and rear fairings are positively plastered in retro-reflective tape. The more light you have coming of the bike, the more visible you are.
Reflectors which fit to the spokes are a complete waste of space. To be seen, the bike has to be right in front of the car, and side on to it. By that time, it's too late. If the driver of the car hasn't seen you by this time, then he's not going to see your reflectors. All they seem to contribute is a little bit of additional weight on the wheels. Okay, it may only be an ounce, but the old adage is "an ounce off the wheels is worth a pound off the frame". I always lose the spoke / wheel reflectors
The orange reflectors fitted to pedals are useful. Because they are in motion (relative to the bike), they are more noticeable, and that motion shouts 'cyclist'. Many pedals can't be fitted with reflectors. Clipless pedals don't usually have mounting points for reflectors. There are a few exceptions though, mainly platform pedals with a clipless point on one side only. These are essentially a regular platform, so can of course be fitted with reflectors.
The reflectors are very useful, particularly if you're out on the bike without lights. We've all seen the Ninja Cyclists, those who seem to go out of their way to remain unseen. No lights, no reflectors, dark clothing. They're not the only ones who go without lights at night. I've done it myself, though not intentionally. You forget to charge up your main battery overnight, and half way through your evening commute home, the battery suddenly dies. It often happens, and then your only means of being seen is your reflectors. Think twice before consigning them to the bin.
N.B. In the photo above, you should note that although it is very visible, it is not necessarily legal. Firstly, the white reflective tape - legal on the sides, but not on the rear. Any reflective surface showing to the rear of a vehicle should be red, and red only. There is no regulation with regards to the red tape. Neither of the lights is legal, despite being the brightest available, as both are LED lights. The lower light is constant-only, the upper is constant or flashing. It is not permitted to have flashing lights on the bike, though you can have them on the person. The reflector incorporated with the lower light is a B.S. approved reflector, so that almost gets me off the hook. To fully comply with the law, I should always have the upper light set on constant mode. I should also have one more light with a filament-type bulb.
Although I have never been stopped or questioned by traffic police regarding the illegal lighting, it might be a different matter if I was involved in a crash during the hours of darkness. Defence Lawyers are always looking for any excuse to get their clients out of responsibility; whilst they might not get off with responsibility, any compensation which might be coming your way could be restricted if you have not complied with the letter of the law.
You need to have some form of lighting on your bike when out after dark. A quick look at Wiggle turns up 108 front lights and 20 rear lights, ranging in cost from £4.99 to £404.99! The brightness of lights ranges from something worse than a worn-out glow-worm, to lights brighter than the full beam on many cars.
First off, those real expensive lights. Are they really necessary? I'm sure that some people will tell you that you need the brightest you can get. You don't. You need something which will illuminate the road in front of you, and something which will make you visible to other road users. Sometimes a light can be too bright - If it dazzles the driver of an on-comiing car, then there's the possiblity that he may be distracted, and that this may cause a crash. If you're only riding around town after dark, then you don't need to illuminate the road in front of you - that's what street lighting is for. Instead get a light that can be seen clearly from a distance away. Usually that means LEDs. Flashing LEDs are much more attention-grabbing and are associated with bicycles, so draw other road users attention to you, and announce that you are a cyclist. However, you should bare in mind the legal status of such lights.
The very brightest (and most expensive) front lights are really designed for off-road use. I'd still argue whether they were really necessary even in these situations. (Digression - Reasons why). Certainly for road use, even on unlit rural backroads, they're overkill. Other road users will certainly be aware of your presence, but again the on-coming driver may be distracted. Even off-road I think that they're overkill. Everything is brightly lit up. There's so much refleted light coming off whatever's around you that even the shadows are swamped. You still get some shadow to remind you it's night, but the experience is changed, and it's not much different to riding during the day.
There are three different types of power supply available for bicycle lights:Primary Cells, Rechargeable Batteries and Dynamo Systems.
Primary Cells. These are the standard "batteries" which you can buy at your local shop. There are two main types, Leclanche Cells and Alkali Cells. Leclanche cells really aren't suitable for use in bicycle lights, and in any case, aren't readily available any more, having been supeceded by Alkali Cells for most applications. The advantage of these cells is that they're readily available and reasonably lightweight. The disadvantage is that they work out very expensive. There is a huge range of lights which run off this type of battery.
You can substitute rechargeable (Ni-MH) cells for Alkali cells. With these, you do save some of the cost disadvantage; the new disadvantage is that rather than slowly runnng down, these cells tend to fail suddenly. Also you should be aware that these cells have a finite life. Eventually they will not take such a full charge, and finally they just won't take charge at all and have to be replaced. They are still cheaper than Alkali cells though. They are also prone to memory problems - you've got to remember to charge them overnight!
Rechargeable Batteries. The advantage of the these systems is cost. Rather than buying lots of batteries, you just have to remember to plug in the charger every night. Like their smaller cousins, these batteries have a finite life. After something like 300 charges, the battery will no longer take any further charge, and has to be replaced. The disdvantage of these systems is cost, both in the very high initial cost of some systems, and also the need to replace batteries eventually. Also these batteries suffer from memory effect - they're no bloody use if you forget to recharge them overnight.
Memory Effect. Okay, the real memory effect. Which is a myth. N.B. This applies to batteries, not cells. The story goes: when you use a rechargeable battery, then you have to use it until it's completely done, then recharge up to max again. Supposedly, if you recharge when the battery is half done, then you'll only be able to use it down to half level from then on. Nonsense. In fact, you shouldn't completely discharge the battery as that can do damage. Batteries consist of several cells held together. Sometimes there will be differences in the capacity between cells in the battery, due to the inherent differences in materials. If you completely discharge the battery, then one cell may become completely discharged before the others. There will then be a current reversal, and the next cell along will reverse and allow current to flow back into the discharged cell. This can permanently damage the battery structure. If you're lucky, then only that one cell will be damaged. You'll be able to continue using the battery, but the capacity will be reduced. If you're particularly unlucky, then the whole battery will be burned out and the whole thing will need replaced.
Dynamos. See following section.
Terminology. A Cell is a single unit of anion-electrolyte-cation, capable of holding an electrical charge. A battery is a collection of cells connected together (in series). Most "Batteries" on sale are actually cells. Alkali AA batteries for example are actually cells. Sealed Lead Acid Batteries (such as used in some of the Smart and Cateye Lights, or a car battery) are Batteries.
Dynamos are a great form of powers supply for lights. Both lights and dynamo are bolted to your bike, so it's unlikely that they'll be nicked. They're always on the bike, so you don't forget them. There's no batteries to run out in the middle of the commute. You don't forget to recharge the batteries overnight and have them die as soon as you try to use them.
There are three types of dynamo available:
Bottle Dynamos: This is what most people think of when they think dynamo. They are shaped like a small bottle which attaches to the top of your seat-stay. When engaged, a loading spring holds the roller at top of the bottle aginst the sidewall of your tyre. These really are hard work, and this is what puts most people off using a dynamo system. There is a problem too, with slippage. When your tyres are wet, then the roller can slip against the rubber of the sidewall, and you lose the light.
There is a new bottle dynamo available, the Litespin, which apparently has a much lighter action, so requires less effort be diverted from your pedalling. Haven't tried one myself, but reports of it are good. Still has the slippage problem though.
Bottom Bracket Dynamos: Something of a rarity these days. The dynamo fits behind the BB shell and when engaged, the roller will press against the tread of the tyre, rather than the sidewall. You can get more tension in the loading spring, so the roller is held more firmly against the tyre. Consequently there is less of problem with slippage. But there's no such thing as a free lunch
You need to pedal harder. Almost like riding on the road and a turbo-trainer at the same time!
There really aren't many of these around now, so if you come across one, it'll probably be on a second-hand touring, Audax, or similar bike
Hub Dynamos: If you want to get a good dynamo system, then this is the way to go. The disadvantage of the Hub Dynamo is the cost. As well as buying the actual dynamo, you also have to get it built into a wheel. Getting a new wheel for this is often as cheap as rebuilding an existing wheel, so they are pricy. But against that, you'll never have to pay any further costs. No more disposable batteries to buy. No paying for electricity to charge you rechargeables. Oh, and rechargeables only have a finite life, usually after about three hundred charges, they are spent and have to be replaced. If you use any sort of battery lights, then the upkeep is very high. Against that, hub dynamos actualy work out very cheap. (Having said that, I am not sure I'd want a hub dynamo on the race bike, so there is still a place for battery lights)
There are two main hub systems, from Schmidt and Shimano. I have the Schmidt's Original Nabendynamo (SON) fitted on my recumbent. Whereas a big problem with other dynamos is the drag when in use, there is hardly any drag when the SON is switched on. The extra effort that goes into turning the dynamo is about the same as the extra effort you would need to climb an 0.1% gradient - hardly anything. To be honest, I have often left the dynamo switched on during the day, and haven't noticed. There is so little drag when the dynamo is on, I can't distinguish it from being off.
Once the dynamo is fitted, there is little to go wrong with it. It's a sealed system, and you don't get muck inside it. All you have to do is return it to the manufacturer for servicing. Schmidt recommend that I get the service done at 40 000 mile intervals, so that's about 10 years between services.
Standard By these I mean self-contained units comprising batteries, case, lens and bulb. Think the ancient "Ever Ready" lamps that were fitted to bikes twenty or thirty years ago. Apart from being Legal, these have nothing further to recommend them. See the section on Rear Filament Bulbs below.
LED lights Although front LED lights on their own are not legal, they are excellent light by which to be seen. White LED technology has only just reached the stage where these lamps can emit enough light to actully see the road, but LEDs have always been great for being seen. They are very bright, and when set to the (dubious legality) flashing mode, they draw attention to the cyclist like nothing else. These are certainly recommended for back-up and secondary use. They have the advantage of very long battery life, so will often get you out of trouble when your main light dies. It's worth keeping a front and rear LED light with you (they're quite lightweight, so are easy to carry) for emergency use.
Rechargeable Systems If you want a real powerful lighting system, then this is the type of lighting system you'll be buying. This is where you can pay some seriously silly money. Anything between £50 and £400. At the lower end of the scale come lights which have either a single 10W lamp, or perhaps a 10W + 5W system. At the top of the scale are lights producing 25W from an Ion bulb, equivalent to 80W from a halogen bulb. Bearing in mind that most cars' full-beam lamps produce 45W halogen. That is overkill. Noboby needs that much light. Up to around 20W total (i.e. a 10W + 10W or a 15W + 5W) is fine for almost all (including off-road) use. Anything more than that, and you've been taken in by the advertisers.
Dynamo LightsUsually front dynamo ligths use a filament bulb, so are completely legal. Some will also have an LED to act as a standlight, so that your lights do not go out completely when you come to a stop. The most commonly used type of dynamo light is the B&M Lumotech, which comes with or without a standlight. B&M lights are good reliable lights, with a good throw of light which is adequate for most commutes on both lit and unlit roads.
If you really want to see and be seen, then the only way to go is Schmidt's E6 and E6-Z lights. These use the excellent Bisy optics to produce a very bright beam of light. Note that although the E6 can be used on any hub-dynamo system, the E6-Z can only be used with Schmidt's own hub dynamo. Neither light can be used with bottle dynamos. Since I started using these two lights I have found that car drivers can actually see me. The dip their headlamps as they approach, and at traffic pinch point, they actually stop and give way to me, thinking that I am a motor vehicle, and expecting me to be faster than I am really going.
LEDs: Although not strictly legal, LED lights have become the de facto standard for rear lights. There are a couple of reasons for this.
First, is that they are bright. They can also operate in constant and flashing modes. Flashing lights, though illegal, are highly attention-grabbing, and also announce that the vehicle is a bicycle. You can't have a flashing filament lights. Whenever you switch a filament bulb off or on, it shortens the bulb life. The filament emits light because it is glowing white hot. When you switch a light on, the filament has to heat up, when you switch off it has to cool down. Eventually, the filament can no longer take the heat gradient, and will snap. (Flashing lights on emergency vehicles use a rotating reflector - again not practical as you would need to carry a further power source for that) If you want a flashing light, then it has to be LED
Second, following on from the above, is the bulb life. Standard filament bulbs have a finite life. Eventually they will go (and Sod's law says it will be at the darkest point of your commute home). You will need to carry spare bulbs around with you, in addition to spare batteries. LEDs don't burn out.
Third, battery life. Batteries will last far longer in a LED light than in a filament bulb light. Sometimes as much as four times longer - and that's when it's in constant mode. If you're using the LED in flashing mode, then they might last three times longer again than in constant. Even if you choose to stay within the law and use lamps that use filament bulbs, it's always worth having a secondary LED light, either in addition to the main lamp, or as a get-you-home backup.
Filament-Bulb Lights: Are heavy, unreliable, blow bulbs, drain batteries rapidly, and aren't even all that bright. They have absolutely no merit, other than to keep you within the legal requirements for riding at night.
Dynamo Rear Lights: Can be either filament-bulb or LED. LEDs are again the better option, if only for one specific reason - the StandLight. When I was a kid I had a dynamo system on my bike. Cycling along quite happily, you'd stop at a set of traffic lights, and all your lights would go out. There were back-up batteries available, but these were heavy and expensive. Some of the current generated by the dynamo would be diverted to charge up the battery (meaning that the lights would be slightly dimmer than without the battery). Now the job of the battery is done with a Capacitor, and we have a lightweight back-up which keeps the lights shining when you stop moving.
It takes very little current to charge up a capacitor, and once charged, all the current then goes to the lights. A capacitor will typically give about five minutes reserve, but you probably won't be stopped for much longer than that. However, they don't work for filament bulbs, as the current drain is much higher. If a light has a StandLight, then the Standlight will be a LED. For rear lamps this will probably mean that the light itself is a LED. For frnt lights, the main light may be a filament-bulb, but there will be a secondary LED which will come on when the main light goes out.
If I had to recommend one system it would be Schmidt. In my opinion, this is far and away the best option for commuting, Audax, or touring. Apart from blown bulbs, it's the most reliable sstem you can get.
It is the responsibility of the individual rider to ensure that the bicycle complies with all relevant local laws when used in public places, and that approved and legal lights are used at all times when cycling in poor visibility conditions.
Many years ago I used to do a lot of night-orienteering. There were some big powerful head-lamps being carted around, but I never used anything more powerful than a Petzl (although I did swap the standard bulb for halogen). When set to the narrowest beam, you seemed to be running towards, but never quite reaching a tunnel of light. Illumination didn't reach the ground (or the surrounding trees) for about five metres in front of you. Your feet and the ground immediately in front of you were in the dark. There was something almost magical in that feeling.
When I started mountain biking at night, I had the same experience. I had a BLT 10W + 2,5W light, though the 2,5W lamp was more of a flood, and illuminated the ground from the tyre forwards. On the bike, I do admit that you need to see the ground immediately in front of the wheel, but it doesn't have to be all that bright. After all, when you're travelling at speed then by the time you see something right in front of the wheel, then it's too late to avoid it, you need to see it to know how to deal with it. The BLT's 10W was spot, and again this gave the tunnel feeling, though with the 2,5W's dim glow around the edge. With the big powerful night lamps, you lose that feeling. They're so bright, there's not much difference from riding in the daylight. Back to Lights