Light Bulbs
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There are so many different bulbs on the market today that it is pretty confusing. |
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The main four types are normal bulbs, xenon filled bulbs, and the 'electra blue' and all-weather types. |
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The xenon filled bulbs are roughly equivalent to normal bulbs, except that they produce 20-30% more light. This is achieved through a thicker filament which burns brighter, and a small amount of xenon gas to prevent the thicker filament overheating. |
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The 'blue' bulbs are either normal bulbs or xenon filled bulbs with a dichroic coating which filters out the yellow component of the light, producing a more blue light. Unfortunately the filament produces most of its light in the yellow wavelengths so by filtering this light out the bulb is effectively a lot less bright and pretty pointless. |
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The all-weather bulbs use a similar dichroic coating to the 'blue' bulbs which instead filters out the blue light from the filament to produce a yellow light. This is supposed to aid vision in fog/rain, etc. The reason being that yellowier light is less easily diffracted, and therefore less glare is produced. (Conversely one would guess, 'blue' bulbs produce more glare?) |
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It has been reported that changing from Halfords 'blue' bulbs to Osram Bilux Super H4 (a xenon charged bulb) will provide an immediate improvement. The Osram bulbs came out top in a bulb test in Auto Express earlier in the year, and the 'blue' bulbs were universally panned). They cost about £18 for the pair from Demon Tweeks, and are similar to the hugely expensive PIAA bulbs in terms of technology and light output. |
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To change the bulbs, there should be a wire clip on the back of the bulb, 1 stem going up either side of the bulb, with a round bit on the top of each, squeeze this 2 rounds bits towards each other and the clip should swing down, the bulb should then come out, refitting is the opposite. |
Headlight Levelling
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When replacing bulbs you may find that the levelling adjustment linkage becomes detached. To fix this, remove the bulb again. Put your fingers inside the headlight and click the moving reflector back onto it's adjuster. Just be careful. |