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  1. #1
    I like bloody ankles
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    Height of light from ground, and effects on terrain contour/shadowing

    The idea of light on bars vs. on the helmet vs. both has been discussed many times over. I've always been a strong proponent of using both, the bar light for flood and terrain contour, and the helmet for throw and seeing where you're looking.

    I was glancing through some beamshots and came across a drastic difference between two images. The two pics below were taken just moments from another, same light and camera exposure, the only difference being that the light was set at less than 1' elevation difference, one image just below bar height and the other about 6" above the bars.

    The difference in terrain contrast is huge, and would be amplified even more if the light were on the helmet. So in addition to the all the optimization of electronics and optics, another piece of the puzzle to provide "quality" light is certainly the height of the emitters themselves.

    Just some food for thought.....

    **Light below the bars**


    **Light above the bars**

  2. #2
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    I generally run my bars as low as I can get them and use my triple mc-e flood on them. It's amazing how much more contrast you get with a low mounted flood.
    Team _________

  3. #3
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    Nice pictures. The shadows realy help pick out the terain on a rough trail with bigger rocks where you realy want to see them. I now run my bar light below the bars which dose help with this. I also have a warmer tint for the bar light as opposed to the helmet light which I also think helps diferentiate the shadows from it.

  4. #4
    Carbon8er
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    I like the lower shot where everything looks smoothed out.

    I'm not big on having shadows project out in front of items on the trail.

    The higher the light, the more it can look over the top of logs and rocks and you can see better what is on the other side.

    I run a helmet light and above the bar light on the downhills and just one light set to low when climbing.

    It's a personal preference I guess.

  5. #5
    I like bloody ankles
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    It is interesting to hear the differing opinions on the shadowing being desired or otherwise. I find it helpful to have some shadowing, but at the same time wouldn't want a black hole behind every slight change in elevation.

    I think this is where the combo of bar and helmet light comes in - the countour is shown, but if you're looking where you want to go, the helmet light will illuminate the backside of all but the largest of trail obstacles. And we all know what happens if you look where you don't want to go.....

  6. #6
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    Quote Originally Posted by dsjc
    It is interesting to hear the differing opinions on the shadowing being desired or otherwise. I find it helpful to have some shadowing, but at the same time wouldn't want a black hole behind every slight change in elevation.

    I think this is where the combo of bar and helmet light comes in - the countour is shown, but if you're looking where you want to go, the helmet light will illuminate the backside of all but the largest of trail obstacles. And we all know what happens if you look where you don't want to go.....
    That is exactly right. The low light works pretty well for level ground, but sucks for uneven areas. My application is a bit different than most of the light builders here. While I will use my LED lights for bicycles, the main thing that started me down this path is off road motorcycling. I currently have about 150 watts of halogen lighting. Enough you say? Not really. In whoops I can see the top of them fine. The bottom is a black hole with the bike mounted light. As a result I've hit unseen bowling ball sized rocks at speed. Let's just say it gets your attention and makes you think about helmet lights.

    The combo of a bike mounted light and a helmet light is the way to go. It's the best of both worlds. The other benefit that two lights offers is reliability. Sudden darkness when your single light fails sucks big time.

    Another situation where a bike mounted light suffers is mountainous singletrack. On tight trails there are places where large steering deflections are needed for sharp corners. On some of them the light can be pointing out into the sky and no putting much light on the trail where you need it. The helmet light helps a lot there.

  7. #7
    Carbon8er
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    vroom, you also need a couple lights on the front axle pointing sraight down. LOL

  8. #8
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    This is exactly why randonneuring bikes usually mount their headlights on the fork leg, or on the leading edge of the front fender -- the lower the light is, the more contour is revealed in the terrain, due to the shallower angle of the light beam W.R.T the ground. I've also found that when riding a bike with a handlebar-mounted light through fog at night, the light reflects off the fog directly in front of you and is quite blinding. A helmet light can have a similar problem.

  9. #9
    I like bloody ankles
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    Quote Originally Posted by jimgskoop
    I've also found that when riding a bike with a handlebar-mounted light through fog at night, the light reflects off the fog directly in front of you and is quite blinding. A helmet light can have a similar problem.
    Strongly agree, I've been blinded my the helmet light in foggy or very dusty conditions as well. I wonder if a warmer tint would reduce that glare, similar to using the yellow fog lights on cars (of course we don't see that much anymore ??)

  10. #10
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    I like some shadows as they do help you see holes that you mght not see until it's too late, but not to the point that a flat piece of grass looks like the suface of the moon as it can make things look a lot rougher than than they actually are.

    I found that Solafilm helps quite a bit in fog. I posted this a week ago.Foggy nights?

  11. #11
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    This has turned out to be an interesting thread. I like discussions like this. After reading what the others have wrote I thought it might be interesting to try a below the bar set-up. With my 600L it would real easy to do, only I would have to remember that the power button would be on the other side...no biggie there. That was when it hit me. If I mount under the bars the light will have all the cables in the way... no, I don't think that would work although I might try it once for the hell of it.
    Tonight I took a ride at a park near me and was amazed that I was having a hard time seeing stuff. ( 600L bar mount/ MCE torch helmet mount ) . Usually my set-up provides more than enough light for any situation but tonight I rode on trails that required a different set-up only I didn't realize it at the time. I was riding trails that were really twisty and knarly so most of the time my lights were not pointing where I needed to be seeing ( which was right in front of me about 15ft. ). Even my helmet light was not helping because it too was pointing too far out. The next time I do that ride I going to point my 600L lower and use a lower level of light. For my helmet I might switch to my P-7 torch which is more of a flood and point it lower on the helmet as well. Once again terrain decides which set-up works the best.

  12. #12
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    I mount my bar light on the front fork Stanchion so I guess it is a stanchion light and then run a helmet light. What I have noticed is there is a point of diminishing returns. Once you get to a certain point mounting isn't as critical. With less light mounting position is key.

    my 1/2 cent

  13. #13
    I like bloody ankles
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    Quote Originally Posted by Cat-man-do
    I was riding trails that were really twisty and knarly so most of the time my lights were not pointing where I needed to be seeing ( which was right in front of me about 15ft. ).
    My normal riding, at least my preferred trail style, doesn't allow me to see more than about 20 yards ahead at any time - very technical, twisty, and overgrown jungle style half-track. For just that reason, my latest light bar light was purposely built for rediculous levels of flood using dual P7's and Boom reflectors.

    my dual P7 build

    The downside is that I'm throwing light in directions that don't help much, like into the sky, but the positive is that my front tire and everything to the sides and 40 yards in front is very well illuminated.

    I also built that light so it can mount well below or above the bars depending on how I configure it, but haven't ridden with it enough to know what works best. I think you're correct that it depends on the trail conditions.

  14. #14
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    Quote Originally Posted by dsjc
    The downside is that I'm throwing light in directions that don't help much, like into the sky, but the positive is that my front tire and everything to the sides and 40 yards in front is very well illuminated.
    If you extend that flat plate 2-3" out ahead/above the LEDs (and maybe polish the underside of it a bit) you'll get a useful beam cutoff that'll block that excess light into the sky, and bounce it down in front of your bike instead.

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