Lights,
SnowBike Action!
The Snowbikers Guide to Mountain Bike Lights
There is a sizeable range of off-road MTB lights on the market, covering an equally large spectrum of prices, and much has already been written about both (See Mountain Biking Product Reviews - MTBR.com). Our aim here is to guide you through some of the technologies available, and as such, this is not so much a review of what's out there as a discussion to help you make your choices.
Night
Riding: why bother?
For many folk, it is the simple answer to the shortened winter days,
and the conflicting demands of work, social life and biking time. Other
people see it as almost a separate biking discipline, with its own equipment,
strategies and challenges. Anticipation-time and reaction-time are cut
down to the beam-dimensions of your lights, and together with the added
navigational demands, the whole experience is a much more intense affair.
Even your usual mtb trails take on a most unfamiliar and challenging
air, and it can be difficult to maintain the required level of concentration
for much more than a couple of hours.
The process
of acquiring off-road mountain bike lights
Psychological studies have revealed that the would-be night rider passes
through several recognisable stages on their way to enlightenment.
i) Denial: "They want how much?!?", "There is no way on earth I'm going to pay that!" etc. etc.ii) Improvisation: Riders at the improvisation stage may be spotted with "that nice powerful mag-lite that lives in the car" duck-taped to their helmet. It ultimately depends on neck muscle strength, but this stage rarely lasts for more than a couple of rides.iii) Self reliance: During this stage, statements like "I could make one of those for a quarter of the price" are common. Depending on individual abilities, some riders never get beyond this phase, and there are complete news-groups dedicated to the subject.iv) Acceptance: Out comes the credit card.
If you need convincing of the merits of Night Riding before committing your hard-earned to batteries, bulbs and wire, why not come along on one of our mountain bike night riding taster sessions, try out a few different configurations and find what works for you.
Handlebar
or Helmet mounted systems?
For road use, UK law stipulates that bicycle lights need to be attached
to the actual bike, but for off-road our money says a head mounted lamp
is definitely the way forward, used either alone or along with a handlebar
mounted one. If lamps are mounted too low, the merest bump in the trail
can create a large pool of shadow that could be concealing anything.
What's more, on twisty singletrack, the handlebars are not always pointing
in the direction that you want to look in. Helmet mounted lights get
around these problems, and are also a great boon when trailside repairs
are required. As an added bonus, because they attach to you, rather
than your bike, there is great scope for cross-over usage, be that adventure
racing or crawling under the floorboards looking to fix that draught.
The only downside with head-mounted lights comes when it is foggy or
snowing; in these conditions the light scatters off particles close
to the eyes, and it can be difficult to see the ground ahead. In these
conditions, a back-up handlebar lamp can be very useful.
| Head torch: | |
| +ve | Points where you look, lessens shadowing. |
| -ve |
Not good in rain, fog, or snow, not street legal, can blind your friends when you stop to chat. |
Batteries
There are essentially 4 different battery formats used in bike lighting
systems. Starting with the oldest (and heaviest and cheapest) technology
first, these are Lead-Acid, Ni-Cad (Nickel-Cadmium), NiMH (Nickel metal
hydride) and Lithium Ion.
Lead-Acid batteries
These batteries, essentially the same as the ones in your car, still feature in cheaper systems. They are heavy compared to other formats, present environmental concerns over their disposal, require a smart charger to get the best performance, and are damaged by being completely discharged. Sealed units are relatively cheap and easily available from electronics suppliers like Maplins, and correspondingly this format retains a following with the DIY crowd.Nickel-Cadmium (Ni-Cad) batteries
Ni-Cad batteries are smaller and lighter than the corresponding Lead Acid version, and need to be fully discharged before recharging to avoid "memory effects" impacting performance. For many years, Ni-Cad was the only suitable rechargeable battery for portable electronic devices. However, they are highly toxic to the environment and will be banned in the European Union in the near future.Nickel Metal Hydride (NiMH) batteries
These batteries are smaller and lighter than the corresponding Ni-Cad version. They are less prone to memory effect than Ni-Cads and do not benefit from full discharge, but they do self-discharge during storage so need intermittent attention.. As there is no Cadmium these units are less environmentally damaging than Ni-Cads.Lithium Ion rechargeable batteries
These batteries are smaller and lighter than the corresponding NiMH version, and currently feature in lap-tops and mobile phones. There is no memory effect, self-discharge is less than half that of nickel-based batteries, and they are more environmentally friendly than NiMH. The format is not fully mature, and as with most cutting-edge technology, there is a considerable price tag attached.
Batteries: Lead Acid +ve Cheap, easily available -ve Very Heavy Ni-Cad +ve Lighter than Lead-Acid -ve Memory Effect, Very toxic Ni-Mh +ve Lighter than Ni-Cad -ve Toxic, but less environmental impact than Ni-Cad Lithium-Ion +ve Lighter than NiMH +ve Technology is still developing: expensive
Lamp
units
A good bulb should change electricity into light without too many losses,
often in the form of heat. Output is measured in Lumens per Watt (amount
of visible light per unit of electricity) and the higher the value the
more efficient the bulb. Another important factor is the light quality
or "Colour Temperature". This is measured in Kelvin (K), and
the higher the number, the closer to pure white light.
There are currently 3 main types of bulbs used in high-power off-road lighting systems: Halogen, Metal Halide and Light Emitting Diodes (LEDs).
Halogen Lamps
By far the most established light-source in the off-road lights market, halogen lamps belong to the incandescent family, in that the light is produced by passing an electric current through a filament. The resistance to the electrical current causes the filament to heat up to such an extent that it emits light. This process is contained within a chamber filled with various inert gases which enhance the performance of the filament and prevent it from burning out by reacting with oxygen.Some manufacturers gain even higher performance from their bulbs by a process known as over-volting. By attaching for example a bulb designed to run at 12 volts to a battery producing 13.5 volts rather than 12 volts, the bulb will produce a comparative increase in both brightness and colour temperature. This improvement comes at the price of a shortened bulb life, but the benefits are generally considered to outweigh this.
Metal Halide Lamps
Halide lamps are arc types in that the discharge of an electrical arc between two electrodes produces light. Performance is increased by the addition of metal halide vapours into the chamber or discharge tube surrounding the electrodes. Because the vapours in the discharge tube are under high pressure, these lamps are also sometimes called High Intensity Discharge (HID) lamps. These lamps represent the pinnacle of bulb technology, and similar systems are to be found in soccer stadium flood-lights. They produce a characteristic hard white light (high colour temperature) and have a longer life span than Halogen lamps.With so many positive attributes one might wonder why anyone would still bother with halogen bulbs, but of course there are some draw-backs too. As with emerging battery technology, the forefront of bulb research and development comes with a hefty price tag, and you can currently buy an entry-level bike for less than some of the lighting systems using these bulbs. Because the circuitry employed to initially create the arc takes time to reset itself, these lights cannot be switched on and off at will, and the life-span of the lamp is affected by the number of ignition cycles.
Light Emitting Diode (LED)
Not so much a bulb as a piece of electronic circuitry, LEDs are an attractive proposition for bike lighting because of their extreme energy efficiency. The units themselves are nothing new, and started appearing in bike rear lights in the 1980's. Because of the lack of suitable "white" units, early front LED lights used fairly ineffective yellow or green LEDs. More recently, higher output white LEDs have become available/affordable, and there are many who predict that the future of off-road lighting lies down this path. The technology is still developing, so it is pricey and there remains scope for improving the brightnes.Some benefits of LED lights are:
• Instant-on/off (unlike HID)
• Flicker-free(unlike HID)
• High Colour Temperature (much like HID)
• Power efficient
• Affordable
• Long bulb life
Another bonus is that LEDs will run with whatever power is available and so dim slowly as battery power ebbs. By comparison, HID bulbs will cut out when there is not enough power.
BULBS: Halogen +ve Cheap, easily available -ve Yellow light, comparatively poor efficiency Metal Halide (HID) +ve Efficient, bright white light -ve On/off problems, high price, cut out at low power LED +ve Long bulb life, white light, efficient, versatile, dims rather than cuts out -ve High price, brightness.
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