prathmann

What "seeming disbelief?" I only questioned your assertion that some lights require that they be removed when locking up a bike since I've never encountered a light that had such a requirement and have almost always left my lights attached. As mentioned I've only had one negative experience with that and it happened to be with a dynamo light - possibly since most battery lights have so little resale value.
As I stated before, I do *not* find that I have the need to remove my lights and rarely do so. But that's been the case whether using dynamo or battery-powered lights. As you indicated, components like derailleurs, handlebars (did have those stolen once), cranks, brakes, etc. are also easily removed but I leave all of those on the bike as well when locking it up.

mikhalit

I live in Germany where the law obliges me to use light systems that do not blind oncoming traffic. Normally I am using a dynamo light like IQ Cyo. Everything is great (if you like dynamo powered lights) except for the visibility in the bad weather situations. Snowfall, fog, thick rain make me think i am not so well visible (and drivers behaviour confirms this).

I had an interesting discussion with cyccommute last winter after which i reconsidered my setup, which look like this now:

- Short daylight season - dynamo lights with shaped beam + MagicShine 2000lm
- Long daylight season - battery powered lights with shaped beam (complaint with German traffic regulations) + MagicShine 2000lm

So, for the areas with high traffic or good street lighting i am using lights with the shaped beam only. It seems to be enough in my area. Once the weather gets crappy I will use MagicShine. When it looks like I can burn someones retina I will point it downwards for a short period of time.

I am sorry if someone's said it already, i have no time to read the entire discussion, but strong lights like MS have different beam patterns too. For example, my MS 876 is more like a flood light, very wide and uniform beam, easy to blind people in front of you. But there are others with much more narrow beams, easier to avoid blinding others, especially when mounted on your helmet. They are great to warn drivers that are going to turn and don't see you coming. And they are not as bad when in low power mode.

Once I am in the woods (i have found a great forest road that is the part of my regular commute now) MS lights are way better than Cyo.

PS. In winter time I never see a daylight when commuting.
PPS. There is another great dynamo light Axa Luxx 70, better than Cyo (wider and brighter beam), not as good as IQ Luxos but twice as cheap.

Jaywalk3r

My lights, if taken from my bike, would fetch $225+ on ebay pretty easily. I paid much less than that for them, but I've had the hosts for a few years, and their market value is increasing. I strip my accessories off when I park the bike. Plus, I like being able to run daytime errands without the lights on the bar.

cyccommute 

I have three $30 lights that I've been using for about a year now. No issues. I had Magicshines that I used for 2 years before than. Again, no issues and I only replaced them because the $30 lights put out more light in a tighter beam. My daughter is using the LED flashlights that I used for a couple of years before that and they are still running strong.

And I have no complaints about the beam shape. I didn't like the Magicshine because the beam was about 35 degrees. I used halogens for many, many, many years with a 12 degree beam which I much preferred and the Crees have that kind of beam shape. A tight spot puts lots of light where you need it while a flood light puts lots of light where you don't.

Sorry, you are wrong about needing different lights for different bikes. I've been riding with lights on my bike since the late 70s so I've had lots of opportunities to observe lights and light patterns. A light that works well for off-road use will work as well...and perhaps better...for on-road urban use.

That's the strength of battery systems, by the way. I only need one set of lights for an unlimited number of bikes. I have several mounts which may, or may not, be attached to the bike, but I don't have to carry around the lights if I don't need them nor do I have to worry about riding only one bike to work, especially during the winter time. If the weather is nice, I can slide the lights onto my road bike or if the weather is rotten, I can slide them onto the mountain bike. If I want to go for a ride on a summer evening, I can slide them onto my cruiser or if I want to do a half century in the dark, I can slide them onto whatever bike I feel like. One set of lights with maximum flexibility and not having to invest a thousand plus dollars is one the reason for a single set of lights.

I can think of lots of reasons. Redundancy comes to mind. Not making the common mistake of thinking that you don't need as much light in an urban environment as you do in rural situations also comes to mind as well. The ability to see into corners with a helmet mounted light as well as the ability to use the helmet mounted light as a warning to particularly clueless drivers (used sparingly, of course). The ability to whatever bike I feel like using on any particular day without having to invest in a complete system for each bike is also a positive.

PaulRivers

Whoa, any chance you know what model of light you use that's battery powered that has a shaped headlight beam?

I'm in the US, and the only light I know of that we have here is the Phillips Saferide - and it's battery life is pretty inadequate so it's difficult to recommend it (< 1 hour with stock batteries, only 1-2 hours with better batteries, and there's some sort of timer inside it so there's no way to hook up external batteries and increase battery life that way).

Whatever you're using probably isn't available in the US either, but I'm really curious what it is...

Thanks for the mention. I did a search, but it looks like it's only available in Germany sadly...

PaulRivers

I just want to point out that he didn't say that one "needed" different lights, he used the words "well suited" and "optimally". I prefer a shaped beam with a cutoff for my commuting - because a lot of my commuting is on a bike path with oncoming bikes and pedestrians. Blinding oncoming cars on a street requires a HUGE amount of lumens - that's a different debate entirely - but blinding oncoming bikes and pedestrians on a bike trail is different, you can blind them with a mere 200 lumen light.

I can understand that you don't feel that you need a shaped beam with a cutoff for you commuting, but you also wrote that -

Where I am - in Minnesota - a flood light is absolutely the best light for off-road mountain biking. A lot of the trails here are switchbacks and tight turns, and a tight beam light is a bad idea.

So...it kinda sounds like if you were doing both road and mountain biking, your beam preferences would be for different kinds of beams for each as well. The flood light would not be optimal for road riding, the tight spot beam would not be optimal for mountain biking.

cyccommute 

You are correct about bike paths and lights. Even a shaped beam would be problematic. That's one of the reasons I avoid using bike paths to commute at night.

I don't agree at all about a flood light being the best for off-road use. Been using tight spots for years and my trails have far more switchbacks and tight turns than in flat Minnesota.

Jaywalk3r

To which MagicShine are you referring? The early ones I remember utilized SSC P7 emitters, which provides a pretty wide beam, without much throw, not very suitable for fast riding.

Cree makes many different models of LEDs. Saying that Crees have a tight narrow beam is like saying Continental tires are super-skinny. Some are, many others aren't. Many different Cree models are used in portable lighting applications, including flashlights and bike lights, including XR-E, MC-E, XP-G, XP-E, XM-L, XP-G2, XP-E2, and XM-L2. Sitting in reflectors of the same diameter and depth, they will all have different beam characteristics. The XR-E, XP-E, and XP-E2 all provide tight, narrow beams. The XP-G2 is a bit wider, with the original XP-G wider still, though neither could be considered floody. The XM-L and the XM-L2 are both very efficient and can be driven pretty hard, so they throw okay by virtue of putting out tons of light, some of which is in the hotspot, but they certainly aren't tight narrow beams. Most cheap, bright lights being sold these days utilize the XM-L emitter. The MC-E puts out a ton of light, but it is a very wide beam, with very little throw.

Not only is the emitter model important, but also the efficiency bin and the tint bin of the emitter matters. During the manufacturing process, emitters of the same model are separated based on how bright they are at a particular voltage and current with a nearly ideal heat sink. Cree identifies these bins with a letter and digit, like Q3, Q4, Q5, R2, R3, R4, T6, U2, U3, etc. The higher the letter, the brighter, therefore more efficient, the emitter is. Within the same letter, the higher the number, the brighter the LED is.

It gets more complicated, still. Each emitter is also binned according to chromaticity. This provides information about the emitter's correlated color temperature and similarity to an ideal black body radiator of the same temperature. For some emitters, the color rendering index value is also specified, which tends be related to the chromaticity.

Most cheap LED lights use emitters from not very high efficiency bins, high CCT (i.e., angry blue cool white tint), and a low CRI value. In other words, the quality of the light produced is very poor. They are fine for "be seen" lights, but not very well suited for "to see" lights. Why is this?

How much light comes out the front of your light isn't what matters. What matters is how much light is reflected back to you by the objects you are illuminating. LEDs produce a very uneven distribution of component colors that mix to make white light. Some are worse than others. While they are technically broad spectrum emitters, there are lots of peaks and valleys if we graph their output by luminous flux versus wavelength. It isn't smooth like, for example, a good incandescent emitter. Consequently, different colors are illuminated at different levels.

Cool white LEDs, for example, provide an overabundance of blues, but not much in the way of yellows or reds. So, if riding in an area with lots of blue objects, those blue objects will be surprisingly well illuminated for the amount of light being emitted from the LED. On the other hand, in an environment with lots of yellows and reds, there won't be a lot of light reflected back at the user relative to the amount of light that coming out of the front of the light. Objects reflect only specific wavelengths of light. If the LED produces those wavelengths in low quantities, then there will only be a low quantity of light reflected back at the user. The rest of the light is absorbed by objects as heat, so is wasted.

Natural outdoor environments tend to have an abundance of warm colored objects, so cool white LEDs are at a severe handicap in such environments. While cool white LEDs tend to be slightly more efficient than neutral and warm white LEDs of the same model, that doesn't mean that users will be able to see more with them.

Neutral white LEDS tend to be a little better, with a more even distribution of component colors. Warm white LEDs tend to be better still. Best are high CRI emitters (CRI of 90+). High CRI Cree emitters tend to be warm, about 3000K. (Nichia offers a well regarded high CRI emitter in neutral white.) The price of such emitters tends to be much higher than the cool white, low CRI versions, so they usually aren't found in cheap lights. They are, however, well worth the extra coin, in my experience.

I actually said different riding speeds and environments (not necessarily different bikes) require different lights for optimal lighting, and that assertion is correct. An easy thought experiment illustrates the point nicely.

If a motorist is driving 20 mph, are his high beams necessary? Of course not. He's not going fast enough to need to see that far ahead. His low beams are perfectly adequate. What if he's driving at 80 mph (or faster)? Are the low beams still adequate? Of course not. At those speeds, he will easily "outrun" his headlights.

One might point out that, while not absolutely necessary, the motorist could use his high beams at low speeds as well as high speeds, one beam shape for both. If we disregard light pollution and courtesy to other drivers, that's a fair point. Except that the car produces its own electricity to power the lights (much like a bike with a dynamo hub). For battery powered lights the rider must purchase and carry the power supply for the lights. Shining light in places it isn't needed is inefficient and suboptimal. That includes shining light farther ahead than necessary for safe riding at typical speeds.

So, while one can certainly make one light work for multiple riding speeds and environments, it isn't optimal.

I would disagree. Off road, I don't want a cutoff beam, which is preferable on the road (Disclaimer: my current commuting light simulates a cutoff beam passably well, but doesn't actually cut the beam off.) Off road, I want a supplemental light on my head, which I absolutely do not want on most roads. My speeds on road are higher, so I need to be able to see farther ahead than when off road. Off road, I'm more concerned (compered to urban street riding) about critters intercepting me along my path, so I prefer a much wider beam than I need on road.

mikhalit

There are few options, B&M Ixon IQ up to 40 Lux, then there is Trelock and that's what i currently use. Really not bad when the weather is Ok. I can't tell what the manufacturer is, but i've seen it popping up in different stores with different names. Mine says "K B Tri lux".

I don't get much running time out of it in full power mode, maybe 1.5-2 hours, 2.5 in 30 lux mode and maybe up to five in 10 lux mode. Well, that means a single trip for me as it's rather long. In summer I am not riding much in the darkness, and for that very reason (short battery life) i run dynamo in winter time.

PaulRivers

I disagree with you that a properly aimed shaped beam is problematic on a bike path at night. I ride mine fairly frequently, and it clearly hits their waist and legs but not their eyes with the light.

You're free to disagree, but that's been my experience. Do you use a helmet light then?

PaulRivers

Ah, thanks for the link. Wish they sold them here...was thinking of trying to get it shipped to the US from Germany (my brothers high end road bike needs a better light), but then I saw you write that it only lasts 1.5-2 hours. I've just found that a 2.5 hour runtime is ideal - any less and I risk running out of battery.

Thanks again for the link and info though. I wrote it down in case I have a reason to come back to it in the future...

cyccommute 

Even lights with cutoffs have significant upwards spray. It's just unavoidable. Add to that the ups and downs of the world and your lights are sure to shine in someone's eyes at some point.

Yes.

PaulRivers

That's not true. The whole point of a cutoff is to avoid "significant" upward spray. If you see some of the European-styled headlight reviews, there are often complaints because there's no effective "spray" above the cutoff, leading to very odd effects when driving -
[IMG]https://i32.photobucket.com/albums/d2...s/DSC04078.jpg[/IMG]

Now usually these lights do have a small amount of upward spray by design so that you get something of a reflection off of street signs and such, but it's not "significant".

In my case, my trail is on old railroad bed, so it's not a problem. But even if it was, I'd rather blind someone 3% of the time than blind them 100% of the time. It's the same thing with car headlights - it's possible with hills and uneven ground for them to point directly into another drivers face. But if you're ever seen someone coming from the opposite direction with their high beams on, it's pretty obvious that it's far worse to be constantly hit in the face with the light than it is to be hit for half a second.

Ah, I've found with a wide beam Light and Motion light (Seca 1400 I think) I haven't needed a helmet light anymore. I'm sure either approach would work.

cyccommute 

I've actually owned a couple of different MagicShines. I believe that both of them had the SSC emitters.

The lights I use...and suggest...have the Cree XM-L T6 emitters. While the emitter may have an influence on the beam width, the optics of the housing has an influence as well. The Magicshine had a shallow reflector that gave a wide beam. The current Cree lights I have have a longer housing with a deeper reflector with a narrow beam.

Sorry but you can't have a lot of light reflected back at you unless you have a lot of light leaving the lamp. The reflected light will never be as intense as the light coming from the source. Why do we chase after higher intensity lights if the light coming out doesn't matter?


Well...

Your example shows a flaw. High beam lights aren't necessary for driving 80 mph in all conditions. There are lots of roads where it is safe to drive at that speed (or close to it) without running high beams and, in fact, they can't run high beams because of opposing traffic. You can still drive 80 mph without the high beam, however. Most of the times that I have used high beam lights is in night time mountain driving where I can't necessarily see around the next curve which is exactly where it is easy to out run your lights.

But, the problem is, that the beams on a car are no more variable than the beams on a bicycle. And many bicycle light come with many more choices of beam strength than just high and low beam. Some come with a low, medium and high output beam, along with a bunch of other modes as well. The beams of a car light are also the same shape whether or not they are high or low beam. Most of them...there are a few exceptions...use the same housing and same reflector. You don't need to change the lamp to change the output. You don't need to change the bicycle lamp either. Is it optimal? No. Does it work? Yes, just as bike lights work in a variety of environments for a variety of applications.

First, I don't believe in that bicycle lights needs a cutoff of any kind. It's just not necessary since we don't ride where we can typically blind on-coming traffic on the road nor are bike lights aimed as far down the road as car lights if you want the light to have any kind of utility. On bike paths, a cutoff is going to be ineffective anyway because of the proximity to other trail users (a typical bike path is only 11 feet wide) which, again, is why I don't commute on bike paths at night.

I don't know why you don't use a helmet light on the road. It has the same utility as off-road riding, i.e. being able to target your light for corners and other objects you want to illuminate. At higher speeds, the helmet light does help with being able to see further down the road while your bar light(s) can illuminate the ground in front of you. It has the added benefit as serving as a warning light in the rare cases where a car attempts to pull out in front of you. Further, the movement of the light has a greater effect on getting people's attention then any blinking light can ever do. It's a more random movement and we humans do very well with picking out objects that are out of place.

cyccommute 

Let's stick with bicycle lights which don't have a sharp a cutoff as European automotive headlamps and leave the car lights for other discussions. If you are walking on a bike path without lights even a little bit of upward light can have a significant impact. Try it on yourself. And, as I said above, the world isn't flat. A slight rise can aim your light directly into a bike path users eyes which would have a much more severe impact. I'm only talking about nonlighted walkers here. Other cyclists who have lights won't be as impacted because they are already running lights which have impacted their night vision.

I choose to blind someone 0% of the time by avoiding the situation.

No matter how wide a beam you have on a handlebar mounted light, it can never match the utility and directability of a helmet mounted light. In fact, a helmet mounted light on a bike path would be the ultimate bike path light. A simple tip of the chin or turn of the head will direct the light entirely away from an unlighted walker.

PaulRivers

Cool.

I've tried it before, and that relates to the amount of ambient light around you.

1 - you're out in the country and have been walking without lights for half an hour.

In this case, any amount of light whatsoever affects your night vision. The shaped beam is still worse, but *any* light has a noticeable impact on your vision - even a tiny keychain light that you point at the ground.

2 - you're in the city and have been walking without lights for half an hour.

In this case, shaped beams insignificant but non-shaped lights are blinding - the ambient light (with no direct lighting of the bike trail whatsoever) bounces off the clouds and everything is lit up enough that minor incidental light is not more than you're already getting. I'm serious - I've been to the remote wilderness where you can't see the hand in front of your face, and I've walked out into a backyard with a fence higher than you are and no direct lighting, and you can see everything ok in the fence and city location. The light from streetlights somehow manage to light everything up a little bit.

3 - you're in the city on a partially lit bike trail.

In this case it's insignificant, but non-shaped lights are blinding - though it depends on where the bike is riding through. If it's in the light patch it's fine, if it's in the dark area (with the non-shaped beam) it's blinding.

4 - you're on well lit trail (there's a section through a sketchy neighborhood that has every inch of it lit up).

It mostly doesn't matter for any beam shape, you have to get into massively overpowered lights to notice. It's basically the same as bike vs car on the street.

xxxxxxxxxxx

But most riding I do is on unlit trails in the city, or partially lit trails (or trails with lights next to them but not actually on them) where I do not find that the shaped beam has a "significant" effect on pedestrians and other bikes - it's definitely a lot less of an effect that my regular lights that I used to use. Peds no longer shield their eyes as I go past.

A trail that evenly rises doesn't blind people - you're on the same plane. Your light shines up higher, but they themselves are up higher. You need a situation where you have a bump, a temporary rise, etc etc so your light shines up while they are down. Those are by definition temporary. Your light can temporarily hit them in the face, but then you have a decline and you're not shining in their face any more. Like I said, I think it's about 3% of the time.

There's no possible way to do that without turning off your lights.

I'm not sure if I want to keep discussing this is you're going to be contradicting yourself. If the incidental light off of a shaped beam is "significant", then there's no possible way have a non-shaped beam on and not be putting "significant" light into other people's eyes. There's no amount of pointing your light down that's going to stop that from happening unless you point your light backwards, in which case it is of no use to you.

You need a light with some spill to the sides on a path. You need to be able to see unlit walkers, bikes, animals, etc without facing directly at them.

The problem is that - I've tried it - just pointing the light not-quite-towards them doesn't work. It's the same as having the light on the bars and having the main part of the beam pointed down at the path. In order to really keep them out of the beam you have to look way to your side, so far over that you're not dangerously not looking at the path in front of you.

You could use a completely narrow beam on your helmet with no spill, but then you need to run a light with some side spill on your bars anyways.

The reason why a shaped beam works for spill is that it's spill is not uniform - it spills to the sides, but not up, where peoples eyes are. Any eyes under about 3 feet (or whatever it is) still get blinded, but most people are taller than that, or riding a bike that puts them up higher than that.

Jaywalk3r

The XM-L T6 is pretty common in low-end lights. That is not to say that no good lights have been produced with the T6, just that it's widely available in the low-end stuff.

The throw produced by a light is dependent on several things, but the single most important factor is surface brightness, i.e., luminous flux divided by emitter surface area. Given two emitters with different surface brightnesses the one with greater surface brightness has more throw potential, period.

It is true that the reflector or optic also plays a role in a light's throw, given a reflector of the same depth and diameter, the light with the emitter with the highest surface brightness throws best. With bike lights, it's desirable to keep the light bezel fairly small. It helps keep the extra air resistance down and save cockpit space. Therefore, emitters with high surface brightness should be preferred when throw is desired.

The XM-L use a pretty large die, 5mm x 5mm, an area of 25 sq mm. Because it is so large, it is very difficult to focus in a reflector. At any time, most of the light is out of focus. An XR-E, by comparison, is 0.9mm x 0.9mm, for an area of about 0.81 sq mm. Although still not a point source light, the small area allows the light to be more easily focused.

The die of the XM-L has an area over thirty times larger than the die of the XR-E, but the XM-L is not 30 times brighter. That tells us that, for a given amount of space on your bar or helmet, an XR-E based light is almost certainly going to throw better than an XM-L based light. Experience with both emitters has shown me that, in the same sized reflectors, it isn't even a close contest; the XR-E throws light much farther.

Given light A and light B, just because light A has more light going out the front compared to light B does not automatically imply that there is more light being reflected back to user A than to user B. There are too many other important factors to consider. The quality, not just the quantity, of the light matters.

Many people keep seeking out higher and higher intensity lights because they simply don't understand that the reason their current lights don't work as well as they would like is not necessarily insufficient brightness.

Okay. Make it 120 mph. The point is that there exists a speed at which low beams project insufficiently to provide enough time to react safely. Switching to high beams increases throw, which increases the time available to react.

That's incorrect. Automobile headlights have different beam profiles between low and high beams. It isn't just increased brightness. The beam shape is different.

Only increasing brightness, which is all changing modes on most bike lights does, doesn't provide much benefit. Even doubling luminous flux is perceived by human eyes as only a very small increase in brightness.


I do like a head mounted light on the trials, but not on the street. On the street, I don't want to shine my light everywhere I look. I don't want to inadvertently blind other road users or pedestrians, or annoy people inside their homes. In particular, blinding other road users diminishes my safety. I generally don't need to see into corners on the street, as the terrain is far more predictable, and street lights are common. I carry a handheld light, easily accessible while pedaling, for use when I need to see something my headlight isn't illuminating. In this way I get the most important benefits of a head mounted light, but I can look where I want without projecting light in that direction.

That depends entirely on the choice of light that gets mounted on the head. Both throwy and floody lights can provide benefits. Throwy lights are better for seeing the trail curves ahead, but a floody head-mounted light is better for seeing into into those curves once you get to them.

cyccommute 

Agreed

I disagree. It depends on the location of ambient light and the area where the trail is.



The Denver area has a few partially lighted trails and none that I would call well lit. Therein lies the problem with riding trails at night. All of the trails that I could ride are generally far from a light source and tree lined. That makes them very dark. A pedestrian walking these trails would experience an ambient light very much like a clear dark moonless night. I've camped enough in the Colorado mountains to know that even without the moon, you can pick out details and walk across a field without problems. But you couldn't run across the same field and if someone turned on a light, you couldn't even walk across it for several minutes. That's why I avoid riding bike paths at night.


A rise has two directions. Depending on which way you are going, you could be on the uphill side which I agree doesn't cause too many problems. However you could also be in a situation where you are above the other trail user at which point your shaped beam basically has no shape whatsoever or, at least, the cutoff isn't doing anything because the pedestrian is below the cutoff of the beam.


You missed the context of my response. I choose to blind someone on a bike path 0% of the time by avoiding using bike paths at night. Some of it is out of courtesy and some of it is because it's not legal along many of the paths that I could use. I have used them in the past but having to stop and talk your way out of a citation really puts a crimp on your average speed. And standing around in the cold in wet bicycling gear while the cop checks your ID isn't all that appealing either.

Any light out there has more than enough side spill to see most anything you'll find on a bike path. I've had a 7 degree halogen which more then enough side spill for bike path riding...if you want to do it. Frankly, I'd hate to walk into the light in the third photo in post #58 . If I were a pedestrian who wanted to preserve even a shred of night vision, I'd have to get 10 feet off the trail to avoid the side spill. It'd be much, much worse than the spill from any light I currently own.

Tonight, do an experiment. Go for a ride or a drive on a road and try to identify the cars with sharp light cut offs from the front of the vehicle. Not from the saddle of a bike, looking at you're own lights with cutoff but as an outside observer. I tried this last night while driving and every single light that I could see coming at me was a round dot. The cutoff did nothing for me, as a driver, until the oncoming car was extremely close. It the nature of the way that light propagates. The light coming from the source will spread out in a cone. If you chop off the top of the cone and shine the lights on a garage door 5 feet in front of the vehicle, you'll see the cutoff but if you turn around and look at the light from further away, the light is a round dot. That's the way that peds view your light in the close quarters of a bike path.

Now some would say that I am being hypocritical because I don't believe in shaped beams for on road use. They would be wrong. Motorists aren't as close to me as they pass and my lights are a lower intensity than the lights of other vehicles that are passing them much, much closer. I'm from 12 to 16 feet away from a driver so my lights won't shine in their eyes when we are both traveling in a straight line. Even on corners or at intersections, my lights are further away from the other road users because of my lane position.

However when you put my lights on a bike path (I don't) or even your lights on a bike path, you are much closer to oncoming traffic...7 to 10 feet closer. Again, this is why I don't ride bike paths at night.

cyccommute 

Where the rubber hits the road or, rather, where the light hits the pavement, you are splitting hairs. Light is a pretty easy thing to observe. The inexpensive light...and we keep forgetting what the original discussion was about...made with the Cree XM-L T6 gets the job done quite adequately. You might be able to spend a whole lot more for a light and get a little improvement but, honestly, I don't that 1 out of 100 people could tell the difference. And once you start monkeying with the optics, all bets are off if you did a blind test.

My point is that you can spend $200 per lamp and use one lamp, maybe 2 if you are feeling particularly wealthy or you could spend the same $200 and get 8 or 9 of the less expensive light. Three of them puts out a stupid amount of light. And, as the technology changes, it's easier to jettison a $25 light then it is to jettison a $200 light.

Sorry but that just doesn't jibe with what light does. Sure there are differences in the intensity of certain wavelengths but you aren't going to be able to notice too much difference with the human eye. If light A puts out slightly more light at 494nm and light B puts out slightly more light at 496nm, your eye isn't going to be able to tell the difference. Even if light A puts out more light 450nm and light B puts out more light at 620nm, you'll see one a little more greenish and one as a little more red but if each is putting out the same number of lumens, you'd be hard pressed to say which is more or less intense. As you said, there are too many factors to consider.

And this applies to bicycling, how? Even at 40 mph...a speed that I can easily reach on my bike as I commute...I don't out run the lights that I use. I've used other, far dimmer, lights in the past and it didn't have any impact on my speed...I did the same speed on the same downhill 20 years ago. The amount of light for seeing the road is more than adequate from any of today's lamps, provided that the lamp output is over ~300 lumens. I certainly wouldn't do the same hill at 40 mph with something like the Planet Bike Flash.


Sorry, I was misstated. The beam shape is different but most of the automobile lights still use the same reflector with a different element for high beams. They, effectively, increase the light output from the same unit.

That's exactly what most cars do as well. They don't have separate reflector, just a different element. As for perceiving the change in brightness, it is noticeable. I don't use the low power settings on my lights because I don't see the point but the difference in the amount of light from low to high power is definitely noticeable.



To each his own. I prefer the helmet mount and, based on a few decades of observation and not a small amount of thought, I don't see any of the problems you perceive with helmet mounted lights. If anything, the ability to move the light makes it less likely to blind other road users because I can direct it away from them more easily than I can a bar mounted light.

PlanoFuji

It is not simply a difference in the amount of light produced by high and low beams, but also where that light gets thrown. Even with the same parabolic reflector, only one of the bulbs is at the focal point (the high beam), the low beam bulb is place above, which effectively puts most of its light down from the reflector.

Best source a quick google turned up:

"American system One filament is located at the focal point of the reflector. The other filament is shifted axially and radially away from the focal point. In most 2-filament sealed beams and in 2-filament replaceable bulbs of type 9004, 9007, and H13, the high-beam filament is at the focal point and the low-beam filament is off focus. For use in right-traffic countries, the low-beam filament is positioned slightly upward, forward and leftward of the focal point, so that when it is energised, the beam is widened and shifted slightly downward and rightward of the headlamp axis. Transverse-filament bulbs such as the 9004 can only be used with the filaments horizontal, but axial-filament bulbs can be rotated or "clocked" by the headlamp designer to optimise the beam pattern or to effect the traffic-handedness of the low beam. The latter is accomplished by clocking the low-beam filament in an upward-forward-leftward position to produce a right-traffic low beam, or in an upward-forward-rightward position to produce a left-traffic low beam." - source

himespau 

I wish I had the scratch for some nice dyno lights. But currently, the amount of night riding I do doesn't justify them. So I use an old magicshine with a AA powered backup that will allow me to limp home if I lose charge. Might get a second CREE light source to put on my helmet and maybe some cutoff lenses for both of them. I kind of like building wheels, but, until my night riding increases, it's easier to drop $30 on a second battery powered light.

PaulRivers

I disagree. Yes, the location of ambient light can have an effect, but everything just ends up more well lit in the city even with no lights that you can see.

Yes, but that's what I mean about "partially lit". The pedestrian will most likely not go for the necessary time for their eyes to be able to adjust to seeing in the dark between lights unless they're just standing on the trail and not moving. Where I am, mostly likely someone else has gone by every few minutes with a bike light to, so they're eyes just are never going to get the chance to adjust to the point you'd get from walking for half an hour in complete darkness.

But this situation is always momentary - blinding them for a second or two before you stop going over the bump, dip, etc etc. If you're on the same path, you cannot be going up while they are going down (in a way that would hit them with the light) for any significant amount of time. A bump, a speedbump, a dip - all of these could cause that to happen, but you quickly end up on the other side of the bump, speed bump, dip, etc. In a situation where the path is going up or down, the other person is on the same incline/decline and so above the top of a shaped beam.

Fair enough, I misunderstood you. It's always legal to ride the bike paths here as far as I know, no matter what time of night.

I disagree, a lot of my bike paths have rabbits and animals on the side than can try to run into your wheel, and when the paths have turns side spill is very very helpful.

A pedestrian in the city mostly just isn't going to be able to get to the point where indirect light is going to affect their night vision, because there's nearly always a certain amount of ambient light, not to mention other bikes regularly coming down the trail with lights.

I think you're not really paying attention to the beam pattern in the 3rd photo - the point is that the light from the light doesn't hit the eyes of oncoming traffic directly. Saying that light reflected off of other surfaces will affect your night vision is a non-issue - because that makes it impossible to have any light whatsoever. Even a tiny pen light would affect that level of night vision. But there's still a huge difference between a light that hits you in the eyes directly, and one that avoids it.

I just don't see any way in which your example matters to a biker. The concern isn't the aesthetics of the light to oncoming traffic.

If you want an experiment, have a friend drive a car down a busy street with your brights on. It will not be the slightest bit of difficulty to tell which car is yours from a distance. I mean heck, when I've accidentally left my high beams on on divided highways (highways with a large strip of grass between the lanes going one way and the lanes going the other), oncoming car after car will flash their lights at me because my high beams are annoying. And they're > 10 feet away on the other side of the dividing strip of grass between us.

I agree with you that it's much less of a concern to be riding a bike light with spill on the road for the reasons you stated. I believe there *is* a point where it becomes an issue - like I think Niterider makes a 3,000 lumen light now - but it's definitely way, way, waaaaaaaaaay higher than when on a bike path or something.

Jaywalk3r

Yes, for some riding speeds and some environments, a XM-L based light is a fine choice. It's poorly suited for my riding style, but if you like it for yours, that's great.

That's why I use a modular system of hosts and light engines. While my hosts are fairly expensive, I can replace the light engines for relatively little. I could switch to a low-end XM-L T6 like you seem to like for less than $15. (Actually, I have such a light engine, but it isn't as well suited as other light engines I also have.) Alternately, I could upgrade to a high-end version of the XM-L, 3000K CCT and 90 minimum CRI, for about $35.

In a few months or a couple years, when the next latest, greatest emitter hits the market, I'll be able to easily and inexpensively upgrade to a high-end bin example of it, too. In other words, by using a modular system, I can get high end light-engines for the cost of low-end lights. As technology changes, there's no need to jettison my hosts, which is where most of my expense is. (Functionally equivalent hosts can be found inexpensively.)

Incorrect. I can take the above mentioned cool white XM-L T6 light engine, as well as a Surefire P91 xenon lamp out in the woods, and despite the XM-L being brighter in terms of luminous flux, the P91 will illuminate things much better; it will appear to be a brighter light, despite actually being dimmer. It shows colors, textures, and other subtle details much better.

Doing a ceiling bounce comparison indoors shows the lights to be of similar brightness, with the XM-L perhaps appearing slightly brighter.

I like to be able to see ten seconds ahead when riding at my typical cruising speeds. That gives me plenty of time to react, as well as providing a cushion for faster sprints and downhills. That means I need a light that throws d = 10 sec * r feet ahead, where r is my typical cruising speed. So, as my cruising speed increases, as one might expect when switching to a different type of bike, I need more throw from my bike light.

Further, I like just enough spill to illuminate my outs, but, optimally, no wider than that. In other words, I don't want to illuminate an area to which I can't turn towards at speed and ride. The extra light is wasted, and I'd rather not waste the battery power producing it. Obviously, at lower speeds, I can safely turn sharper than at higher speeds. So at lower speeds, I prefer more/wider spill than I find desirable at higher speeds.

So, as my speed increases, I want more throw and less/narrower spill. As my typical speeds decrease, I want less throw and more spill.




You are contradicting yourself. Just above, you acknowledged that there is, in fact, a difference in the beam shape of a car's low and high beams, that it isn't merely a change in brightness.

It's noticeable because the beam shape changes significantly. If it were just a change in brightness, it wouldn't make such an obvious change. Industry experts have found that a light needs to increase its output by 40 percent in order for that increase to be barely perceptible in a side by side comparison. For a large increase in perceived brightness, the brighter light needs to produce at least a few times the luminous flux of the dimmer light. So, if we try to provide the changes required by increased speed with only increased brightness, we need a few times as much battery capacity. A better solution is to find a light with a beam that provides more throw and less spill at the same voltage and a similar current.

A bar mounted light points straight ahead, just like a car headlight. On the other hand, my head is always moving (see: "Keep your head on a swivel." in my signature.), so a head mounted light would certainly inadvertently blind some people.

noglider 

Yes, it's easier, and I can't blame you for doing it, since that's the way I generally approach it. But I've now bought so many lights now, if I had started with a good one in the first place, I would have saved money. Did you see that my setup with dynamo, headlight, and taillight ended up costing me only about $160? I didn't add labor for building my front wheel, so if you pay people to build your wheels, you have to add another $40 or so.

PlanoFuji

What hub dynamo and light did you settle on? I am using Shimano's that ran me about $100 just for the hub, so with spokes and rim (I built it myself) it ended up at about $200 just for the wheel.