I thought this was worth sharing with the group:
I sent an email to Daniel Stern at his company which is considered one of the premier lighting consultants. I asked him about the mediocre throw of the stock twin bulb HD headllight. This is what he had to offer:
Yes, the twin-bulb lamp looks nifty but is a poor performer. There's no magic bulb that kicks up its performance to where it needs to be.
The main problem you're up against is the optics in the stock headlamp.
They're focused to give a pretty wide spread of light, but there's not
enough seeing distance ahead.
Option 1-good halogen headlamp:
Put in a Cibie lens-reflector unit ($79)
and an Osram 70/65w bulb ($21.59, maybe get a spare), aim the lamp carefully
and correctly per
http://www.danielsternlighting.com/tech/aim/aim.html ,
and you'll find you're much better able to see at night. There are other sources for the Cibie headlamp I recommend, but I do believe I have the best price and I try hard to have the best service.
Proof of pudding, see
http://www.hdforums.com/m_3263504/tm.htm
Option 2 - LED headlamp:
There are a couple of 7" round LED headlamps on the market. The one from Truck-Lite (same as the one from GE) costs around $325 and I have to say it's definitely better than Truck-Lite's first try at it, but oddly it is designed to the old sealed-beam photometric standard rather than the new-for-1998 upgraded photometric standard. The one from JW Speaker (in Wisconsin, 20 minutes away from Harley HQ) is a good performer, designed to the newer photometrics, and it is well made of good quality materials. Spendy, though; it costs around $450/ea, and some riders don't like its low beam performance characteristics. This can be bought through Harley Parts and Accessories (they call them the "Daymaker" LED headlamps). LED headlamps are still on the left (upward) side of the development curve; over the next five years we'll see more options with gradually increasing performance and gradually decreasing cost.
Option 3 - HID (Xenon) headlamp:
"HID kits" in halogen-bulb headlamps (any kit, any headlamp, any vehicle) do not work safely or effectively, which is why they are illegal. See
http://www.danielsternlighting.com/tech/bulbs/Hid/conversions/conversions.html . This holds true whether you buy the "HID kit" and the headlamp housing together or separately.
There is exactly _one_ legitimate, legal, well-made, good-performing HID headlamp to fit your Harley. It is built around the Hella high/low-beam projector used in current-model higher-end Mercedes, BMWs, Audis, Porsches, etc. Beam performance is _vastly_ superior to what can be obtained with tungsten/halogen light bulbs in any optic unit, also much superior to any of today's LED headlamps. Bulb lifespan is about 10 years. Beam focus is broad, robust, and highly precise, with excellent control of glare and stray light; when these lamps are aimed correctly they are inoffensive to other road users on low beam. They are also fully road-legal. It is also very costly; price is about $659. This is easily the best-performing headlamp to fit a Harley; I keep it in stock.
"Passing" lamps:
If your Harley has passing lamps and you want to
upgrade them, be advised they will never provide much of
any light useful for seeing -- they're too small. However, they can be put
to good use as conspicuous lights to help other road users see you in time
to avoid doing something dumb in front of you. The original units create a
beam only 11 degrees wide. You can replace these beam units with selective
yellow wide-beam units (40 degrees wide) so that people pulling out from
side streets or adjacent lanes will be more likely to notice your presence
and position before doing so. I no longer stock the #4415A passing lamp upgrade beam units, but you ought to be able to find them quite easily, either locally or online, with a search on *4415A sealed beam *. Insist on a good brand (GE or Wagner), and see to it the ones you get are
*yellow*, not the bizarre dark brown color some of the lenses have been coming through with.
Lamp aim:
Even if your old headlamp was aimed properly, the new one must be checked and aimed to spec. Have a helper hold the bike upright while you aim the new headlamp per the "VOL" instructions and the passing lamps per the "VOR" instructions at http://www.danielsternlighting.com/tech/aim/aim.html and your nighttime seeing will be a great deal safer and easier.
