Bike Lights Made Easy

By Moz,

Most of us have seen cyclists at night riding with no lights, or almost as bad, ineffective lights. I sometimes worry that I am no more visible than the darkened figures I see. This pamphlet will have a go at explaining what I've done to make myself more visible.


Firstly, reflectors are the cheapest way to make yourself visible at night. Any bike shop will be able to sell you cheap but effective front and rear reflectors, and most will fit them free of charge. Remember that bigger is better, the 3cm by 5cm ones only meet the minimum legal requirement and are not as good as the equally common 5cm by 7cm ones. Wheel reflectors are also a good idea.

A second source of reflected light is reflective tape. This can be got from most marine shops or The Cheeky Monkey Cycle Company, in Pitt St near Central Station. Wiping the frame clean and applying tape will work wonders - a strip down the front of each front fork and the same on the back, plus the side of any available tube will make you much more visible. At $5/m that could be the best $10 or $15 you can spend.

Beyond this you can add a reflective vest or bands, or a fluorescent yellow raincoat with reflective stripes. These cost about $20 for a simple reflective Y harness to whatever you're willing to spend on a rain coat. One cheap option is to ask construction workers for any old reflective gear they don't want.

Rear Lights

For lighting, the red LED lights are hard to beat. Almost any light will do, but I prefer ones that run on two AA batteries as the batteries last a lot longer, and the lights tend to be brighter. These lights cost around $20-$30 each, and I prefer to use two - one constant, one flashing. The theory here is that the flashing one draws attention, but our eyes have trouble estimating distance to a flash accurately, so the constant light gives the eye something to focus on.

Jaycar (in York St near the QVB) sell large LED emergency lights with 18 LEDs for $30 each. These take 4AA batteries to give about 24 hours light in flashing mode. With a little work it is possible to mount one of these on a bike, as you can see on the bikes around this stall. The easiest way is to use a metal reflector mounting bracket and replace the screw that holds the back cover of the light in place with a longer one. A 20mm long M3 screw will do, and allows the light to be fixed to a metal reflector bracket using that screw. A more secure mount involves drilling holes in the light and bolting it to something solid.

Front Lights

An LED front light is basically useless, in my opinion. An alternative to those is the xenon strobe lights that are available from many bike shops for around $30-$50. These run on two AA batteries and flash once or twice a second. Not for very long, but they are quite visible. With rechargeable batteries they flash faster and battery life is not such a concern. I tend to use these as backup lights that are always on the bike (for when I forget my battery or get caught out).

Far better than this is a bright, constant light that you can see by in dark cycle ways, and which can be easily seen by motorists even against a brightly lit background. There are a variety of small halogen front lights available, and again I have a distinct preference. The Cateye Micro takes four AA batteries and is popular with AUDAX riders (who ride long distances at night, so want light weight and reliability above all else). These cost about $40 and most bike shops can order them in if they don't have them in stock.

If you are going to be riding at night a lot a decent dynamo front light may be a good investment. The newer European systems are very low drag and put out a decent amount of light. Cheeky Monkey have the Lightspin dynamos and various lights, costing about $180 for the dynamo and $40-$60 for the lights. I use a hub dynamo to avoid the hassle of an external dynamo, which invariably gets knocked about and needs adjustment. Losses are lower again with one of these.

For more serious lighting there are a variety of off the shelf systems that use a larger battery and provide anything from 10W to 50W of light. Enough to get motorists flashing their lights at you if you're not careful! These cost a bit, the basic LightStick model being about $120, and the better ones tend to be more expensive. A second, more important factor, is that they tend to come with cheap and nasty "dumb" battery chargers that wreck the battery over time (resulting in a new sale for the manufacturer in many cases). Bulbs for these also seem to be a specialist part costing $20 or so from bike shops.

Build Your Own

A cheaper alternative to this is the DIY model. For about $100 you can build your own 12V halogen lighting system and have as much light as you want (or are willing to carry batteries for). On the web you can find numerous sites detailing the process, including several from Sydney riders. The MTB gang were initially driven to this by their need for 100W lighting rigs for night riding, but they're a great way for the rest of us to get cheap lights.

The basic system is a 12V battery, a 20W halogen bulb ($5 from KMart or just about anywhere else), a charger and some simple wiring. Using only a pair of wire cutting pliers, a screwdriver and parts bought at Jaycar you can get a light on your bike that is as bright as some car headlights. It's not even very hard.

Jaycar sell all the bits you need, and their Sydney store is at 129 York St, ph 9267 1614. All up cost from them is about $80, plus $30 for a giant back light. Places like Dick Smith and some lighting outlets will also have most of it, but the charger may be a little harder to came by.

The big decision to make first is how you want to join the electrical wires up. The battery will have automotive style " spade connectors" on them, so if you have one of those crimping sets that is the easy way to go. If you own (and can use) a soldering iron that's the method I use, and if you're a genuine novice the terminal block method described below will also work. The instructions are based on screw terminals, on the basis that if you're doing anything else you will hopefully be experienced enough to work out the changes. If you are, a switch and the plugs are a worthwhile addition (but are not essential). part numbers and July 2001 prices

Front light
Description Code Cost for oneCost for ten
12V, 4.2AH SLA Battery SB-2484$39.50 $31.45
12V SLA smart charger MB-3517$32.95 $26.45
12V 20W halogen bulb SL-2730$5.99 $4.75
socket for bulb SL-2735$3.75 $2.95
medium duty speaker wire- 2mWB-1706$1.30 $6.50
female spade connector PT-4507$2.20 $19.50
terminal strip HM-3196$1.85 $1.65
2 pin plug/ socket (need 2)PP-2020$2.25 $1.95
Rear light
Description Code Cost for oneCost for ten
Giant LED light ST-3039$28.00 $22.35
AA NiMH (>1500mAH) SB-2442$4.30 $3.75
smart charger, up to 10 AAs MB-3512$69.95 $55.95

The plug and socket (italics) are optional and you need to solder them. Note that you get 8 spade connectors in a packet, and you need two. I do occasional bulk orders for these things for Critical Mass Sydney (, where we get a further 10%-25% off the 10+ prices. MassBug may do something similar if there is enough demand.

Once you have the bits in a pile it's time to start thinking about how and where to mount it one the bike, as this determines how long you make the wire. It has to go from the battery to the handlebars, and if you are going to put the battery in a pannier you will want a bit of extra so you can close the pannier when it rains. 2m is enough for most situations.

two terminal blocks Using screw terminals for beginners: The terminal strip is two screws wide, and usually ten long. Electrically they're connected in pairs across the strip (vertically in the photo), and the strip is designed to be cut across, allowing you to make 5 pairs (or 10 single) connectors, or whatever. Don't cut it yet, just get an idea of how it works.

To use these first loosen one of the screws in the pair you're using. The screws are captive in there, so just loosen it right off. Now cut the plastic insulation off each wire about 5mm from the end by running a knife around it (gently - don't cut too many of the tiny copper strands inside), and pull off the little bit of plastic that is now separate. Twist the exposed strands slightly and poke the wire into one section of the terminal strip. Now do the appropriate screw back up to hold the wire in place.

a terminal block, wired upPut the light socket on one end of the wire: separate the two conductors by pulling them apart, for about 5cm. The wire has a figure 8 cross section, and you're turning it into two figure 0's. Now cut the insulation off both the conductors as above, and attach them on one side of the terminal strip. They should be next to each other, as you're going to cut those two off the strip in a moment. Once the wire is in place, get the light socket. It should have two wires coming out that end in small copper tags. Put those into the bits of your terminal strip that match the terminals with the wire in. You should now have something that is similar to the photo. Cut those two terminals off, using a sharp knife works best in my experience.

a spade connector or twoAt the other end of the wire you need two spade connectors for the battery (as in the photo to the right). Strip back the insulation as before, but this time put spade connectors on the ends. The wire pokes into the plastic covered bit, then you crush that with pliers (or a special crimping tool if you have one).

That's it! You now have the wiring done, and if you plug the bulb in one end and the battery in the other it should go. This is how you will be turning the light on and off if you don't have a switch.

Note: the charger will come with spade connectors on it, and the Jaycar smart charger will not charge if you connect it up the wrong way round. Which is another reason for buying that one.

attaching to bike 1attaching to bike 2 Attaching to the bike This can be fun. I use an old spoke bent round and bolted on, with one on each side of the bike as shown here. You can attach a hook like that to standard handlebars using a hose clamp, of just wind it around the bars. If you do this it's a good idea to paint the back of the bulb to reduce the amount of light coming out the back of it.

One step up is to use a plastic cover. Those bulbs fit nicely into a car towball cover, or you can often find the right size bits in the plumbing area of a hardware shop. Make a hole in the back for the wire to go out and you're away. Attaching the resulting cylinder to the handlebars can be done with two hose clamps -one around the light, and one around the bars. A couple of bits of old spoke under the clamp running forward and hooking over the front edge hold the bulb in place.

If you're really keen you can fold up covers out of aluminium sheet (an old drink can) or use an old bike light to give you a removable fitting. At the really expensive end are some cheap car driving lights, which use 50W halogen globes like we do, but use fancy plastic cases. They cost $50 or more a pair, but do look very pretty. Or the bent spoke approach does the same job in a less complex way. You decide.

Useful Web Sites

These came from a quick search at for "build 12V halogen bike light"

Petes Bike Light Page
Resources for Bike Light Builders
list of links to other pages
Home made cheap bike light:
Moz's Bike Stuff