Tail lights: how bright is too bright?



lectraplayer

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May 11, 2014
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I recently got one of those "night vision" red flashlights for deer hunting and have been trying it out. ...and one thing I thought to do is strap it to my bike as a tail light. ...but I haven't rode with it yet. Partly because it's 2000 lumens for the equivalent white model, and turned down to low, it is still plenty bright enough to dazzle me as I look at it from about 20 meters back. With that in mind, about how bright for a high power red LED tail light would you say is too much, such that I begin to dazzle motorists when riding of a night?
 

Froze

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Jul 13, 2004
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2000 lumens is just plain nuts man, 100 to 150 lumens is plenty bright enough. Car tail lights are only around 80 to 90 lumens and motorcycles are about half that! However, car and motorcycle tail lights have a much greater surface area than a bicycle light will have so they are more visible which means you have to make up the fact that the bike light is way smaller in surface size by increasing the lumens to say 100 min to 150 max.
 

lectraplayer

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May 11, 2014
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I thought so, but at least I know it's there. :p

Even with that, I'm unsure exactly what the actual brightness of my light is, but the white model is 2000 lumens. The wavelength of the light would impact the actual measurement.
 

Froze

Well-Known Member
Jul 13, 2004
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I thought so, but at least I know it's there. :p

Even with that, I'm unsure exactly what the actual brightness of my light is, but the white model is 2000 lumens. The wavelength of the light would impact the actual measurement.

Even on the front of a bike 2000 lumens is overkill unless your riding on single track in pitch darkness. For roadies a front light with 800 to 1,200 lumens max output (depending on what you can afford) is plenty good enough, but in normal riding you'll only use half of that, the extra power is for less than idea weather conditions like rain. For comparison an average car headlight puts out 1200 lumens on high BUT it's an aimed light not just casting a light everywhere, HOWEVER since a bike doesn't go 70 mph down a highway you don't really need 1200 lumens, another however though is the bike headlight surface area is smaller so you have to make up for the lost of surface area that a car has with a headlight in the range I mentioned.
 

Froze

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Jul 13, 2004
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There is new type of tail light on the market made by See Sense that puts out 250 lumens on their brightest model, but that one works differently then other lights, it grows in intensity as a car gets closer, the theory is that as the headlights get brighter it could wash out dimmer lights, however since this one gets brighter it won't get washed out. I think this light is probably the best light on the market from what I've read and seen. Yes it's brighter than what I originally said but it's not eye blinding from a distance irritating motorists and cyclists, in addition it is a wider dispersed light pattern. They also make a less expensive one that puts out a max of 190, I would think that would be plenty of light.

The headlights they offer work the same way but these lights are more for grabbing the attention of a motorist and not for seeing the road with because it's a flasher.

Even if you can't afford this level of lighting at this time you can alway get one later and add it to your current light, this way you can have the brightest one on the seat post or seat bag, and the other on your helmet. Two lights are better than one.

http://seesense.cc/