I'm planning on buying this LED Torch with this helmet mount.

Could I blind oncoming drivers?

Helmet mount from Amazon

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    It may not be such a good idea to fix something to your helmet as it reduces its ability to slide over the tarmac in a crash. This sliding is important to avoid concussion. – gschenk Mar 20 '17 at 19:23
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    @gschenk when I weigh up the risks I come to the conclusion that helmet lights are much safer than not having them. Near misses are common, and being more visible can only help with that. Also vicious potholes can be spotted with a suitable head torch further away than with a well adjusted front light. Bad crashes on the other hand are very rare. – Chris H Mar 20 '17 at 22:12
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    @gschenk: It looks like the mount will get ripped off / shear off cleanly in the event of a crash. – Jörg W Mittag Mar 21 '17 at 0:31
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    mounting things on a helmet should be done very carefully. See telegraph.co.uk/sport/motorsport/formulaone/michael-schumacher/… – njzk2 Mar 22 '17 at 15:39
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    In some countries (Germany, Holland) bicycle lights must meet standards to prevent dazzling other road users. I have no knowledge of those standards, but I expect a helmet light would not be able to meet those standards and a touch strapped to the helmet certainly would not. – mattnz Sep 15 '19 at 1:00

I have a helmet mount very similar, and yes its totally possible to dazzle and annoy any other road user, from pedestrians to other cyclists to motorised vehicle drivers.

Benefits to a helmet light

  • Its high up above the ground and higher than handlebar lights, so other road users can see it over cars.
  • The beam follows your head, so you can light up the thing you want to see.
  • Retro-reflectors everywhere! Since the light source is near your eyeballs, retro-reflectors work really well and from a very long way away. A sweep across a dark road will illuminate all those car bumpers and street signs and mailboxes and jogger's jackets and sports shoes.

Disadvantages of and risks due to a helmet light

  • Drivers might get dazzled. I've had a bus driver yell at me from his rolling bus because of my head light. Admittedly he was more annoyed by the flashing, so after some research I decided to leave it on solid.
  • Retro-reflectors can be dazzlingly bright when lit up at close range, destroying your own night-sight.
  • Snaggage risk - your torch/flashlight is a fairly respectable-sized hook and can catch on low hanging branches. I've caught mine on a washing line at low speed and basically "clotheslined" myself with the chinstrap.
  • Helmet Function may be compromised by the holder. Michael Schumacher's skiing accident was exacerbated by the gopro camera mount that focused impact forces on one point rather than spreading them over the head like a helmet is supposed to. If you were crashing, then the mount should snap off. What if it didn't snap, or if you impacted vertically onto it?
  • Weight - torch batteries are dense and the added weight can be noticeable.


I have mine mounted fairly far back on the helmet, so the torch front barely clears the top. This reduces snag risk.

The mount is held on by a minimum of velcro, and there's a separate hand strap used as a second line to stop it getting lost.

As mentioned, I use it on solid mode now, however the focus is set fairly tight. At night my normal posture puts the lights on the road surface around 4-5 metres in front of my wheel. I tend to look up with my eyeballs rather than my neck.

However, if a car presents in a manner that crosses my path and may require them to give way (to yeild) then I will point the beam below the driver's door. If I'm passing a parked car that has a person moving in the drivers seat I might light up their wing mirror.

I'd rather annoy someone than get doored by their inattention.
While I won't deliberately dazzle anyone or anything, my priority is everyone using the road arrives home safe.

EDIT Here's a pic showing what I do, for clarity.

enter image description here

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    "I'd rather annoy someone than get doored by their inattention." Exactly. I do a lot of city riding and often at night. I feel that I am less noticed when I have a solid beam - maybe to drivers I appear as just another car? I keep a solid beam and then a flashing beam pointed at the ground about 10-15 m in front of me. – jcbrou Mar 21 '17 at 16:45
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    @SuspendedUser From the point of view of the person who's just being dazzled, "too bright" versus "badly adjusted" is a distinction without a difference. The problem is that too much light got directed into my face and I don't care how it gets fixed. – David Richerby Mar 21 '17 at 22:45
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    Thanks for adding the sketch, this makes it much clearer. Lights can really be tricky and depend so much on the environment (if you cycle mostly on lit city streets or darkness, on-road or off-road, shared paths busy with other people or very remote etc) and I think it's a good idea to have multiple lights that you can also switch off when not needed. – Stephan Matthiesen Mar 22 '17 at 13:46
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    @DavidRicherby You should care. Just dimming a badly adjusted light to a lower level (or downgrading it) where it doesn't bother you (the person it's badly aimed at) means that now the person using the light can't see. – Deleted User Mar 25 '17 at 22:18
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    @SuspendedUser That is, quite literally, not my problem. – David Richerby Mar 26 '17 at 9:16

Not necessarily blind, but annoy and distract.

For oncoming traffic, the best lights are ones mounted below eye level and that limit the upper beam. The easiest way to check for this online is to see if a light is sold by a German mail order store and whether it passes StVZO regulations.

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  • Those lights are good up to a point but over about 30km/h with no streetlights or on tight bends they're useless. – Chris H Mar 20 '17 at 22:19
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    @ChrisH But that's no justification to blind oncoming drivers, other cyclists and pedestrians. If you often go through dark areas, get two lights: a good, dipped one that's always on, and a brigh floodlight that you can switch on when it's dark and nobody else is around. Just like the dipped/full light system for cars. – Stephan Matthiesen Mar 21 '17 at 7:49
  • @StephanMatthiesen I agree completely. In fact even on purely selfish grounds - people can't see where you are if you dazzle them. I run with a light on the bars and one on my head, both dipped in both power and angle unless necessary. My head torch is a narrow beam unlike the one in the question, which I wouldn't recommend. – Chris H Mar 21 '17 at 9:26
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    @ChrisH Sorry that my comment came out harsher than I meant it. – Stephan Matthiesen Mar 22 '17 at 13:42
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    @StephanMatthiesen no apology needed. Opinions on the subject are strong (if mine are anything to go by) and given that some people dazzle while others hide in the shadows we need to air them. – Chris H Mar 22 '17 at 19:02

Have a friend wear your helmet with the light mounted on it like you planned. Then go to a small residential street at twilight and see for yourself whether it is too bright. Bring a car and try passing each other a few times, both in the twilight and when it gets completely dark. If it blinds you, see if dimming the light or aiming it down helps. If not, find a different light.

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  • Why twilight? Total pitch blackness would be a better test. – Criggie Mar 21 '17 at 23:32
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    Twilight so that you have time to get set up before it becomes pitch black, and then can see it in both conditions. Although I don't know if OP is planning to ride in places without street lights. – SLR Mar 22 '17 at 0:32

Problem with most flashlights is that they have a circular and symmetrical beam, ie they throw as much light up as down. This is good for MTB as you want to see branches flying into your face. For a bicycle, this is not what you want. You need special optics, which the Germans normalized (google StVZO bike light).

Result is something like this (as an example):

enter image description here

Notice the beam's sharp cutoff, very little light is sent upwards, to the eyes of incoming people. This is what you need.

Now, you should find a light of this type, small and light enough to mount on your helmet.

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  • I've gone for an StVZO light mounted on the handlebars. If I were to get an StVZO light mounted on my helmet I would have to find a mount that easily breaks on impact so that my neck does not get jerked in the event of a crash. If anyone can find an example of an StVZO light with a helmet mount that breaks on impact then if the handlebar light I bought is not good enough I will buy it. – usainlightning Mar 22 '17 at 14:09
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    If you find a small and light StVZO light for your helmet, I'm interested in a link. The helmet mount I used for MTB flashlight was a simple piece of styrofoam cut to shape and a single turn of PVC adhesive tape to hold the light to the helmet. – bobflux Mar 22 '17 at 14:24
  • "they throw as much light up as down" only if mounted level, which is not how a helmet light is meant to be ordinarily used. Sure, you can tip your head up so that it is projecting level if you want to see something far ahead, but normally it would be aimed down, sending less light up than a fixed bar light would need to if it was going to give you any ability to see into the distance. – Chris Stratton Sep 17 '19 at 4:37

Just about any light can blind/startle an oncoming driver. I'd suggest using it dimmed, that way it might last a little longer and you're less likely to cause an accident. As long as you avoid shining it directly at a driver, it shouldn't be a problem.

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    The problem is that "avoid shining it directly at a driver" means "avoid looking at a driver" and one's natural reaction to an interesting moving thing just over there is to look at it. – David Richerby Mar 20 '17 at 18:59
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    @DavidRicherby If you point it down a little, you can still look at them but avoid shining it in their eyes. – Philip Gibbons Mar 20 '17 at 19:10
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    Your comment completes the answer. By having it angled a notch below eye level you illuminate the road where you need to without inadvertently dazzling anyone. Hands-free control of where it points make a big difference. – Chris H Mar 20 '17 at 22:15
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    In Germany, it is required by law that the bike's headlight must be adjusted such that the centre of the beam is at half the headlight's mounting height at a distance of 5m. Failing to adjust the light properly will probably not get you cited, but it will get you in trouble if you cause an accident by blinding someone. I don't think there is an explicit rule about helmet lamps, but a judge will probably draw an analogy to the headlight, and use one of the catch-all paragraphs about recklessness or something like that. – Jörg W Mittag Mar 21 '17 at 0:39
  • @DavidRicherby - once you've ridden with a helmet light for an hour or so, you realize that there's a difference between where your head is pointed and where your eyes are pointed, and using that difference is key to courteous sharing of the path or road. You can light what you need to light, and look at what you need to look at, even when they aren't the same thing. – Chris Stratton Sep 17 '19 at 4:40

I began to rather dislike helmet mounted lights on oncoming cyclists. Fortunately I don't see them very often riding in a city. Yet from the dozen or so I met last Spring and the Autumn before two brought me in uncomfortable situations.

In both cases I was descending on a bi-directional multi use path (1% slope) at moderate speed (25 to 35 km/h).

In the first case a cyclist quite a bit down the way was looking at me and shining their light directly into my eyes. Opposite traffic was moderately dense cyclists were overtaking. Being dazzled I could not tell how much room I had to the left, and went as far to the right hand edge. However, I had difficulty identifying the edge of tarmac as well. I went a bit too far, onto wet fallen leaves and rough ground, yet could stay stable.

In the second case a slow rider with a head mounted light cycled that path up. A rider behind with weak or no light was preparing to overtake. I mistook the high mounted light of the first rider for the light of the second rider and did not notice that they were already overtaking and I had to move to the edge of the way. This led to a very close, fast path with the second cyclist.

Much more often I am dazzled by badly adjusted, very bright, fixed bike lights. This is especially a problem early in the Autumn when the weather is still fair but the sun sets early. Lots of people are still riding but are inexperienced with their lights. As soon as it gets cold, only experienced riders are left (or at least they were yelled at often enough to fix their lights.)

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    In these situations where you are blinded by someone else's light, it may be a good idea to stretch out your hand such that the hand is in between the light and your eyes, allowing you to see what's actually next to the light. Place the edge of your hand carefully. Done right, you'll be able to see more with your arm/hand obstructing your view than without it. If they are pedestrians with torch lights, please stop by and tell them that they are doing their safety no favor by blinding bikers, tell them to aim at the ground instead. It's the only way they might be going to learn. – cmaster - reinstate monica Sep 16 '19 at 0:44
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    35km/h on a shared use bidirectional path is far from a moderate speed. There an element of blame here that does not appear to consider maybe you are (at least in part) at fault. – mattnz Sep 16 '19 at 2:22
  • @mattnz it is a long downhill stretch, these are the typical speeds northbound traffic flows at. – gschenk Sep 16 '19 at 9:20
  • @cmaster I often do that. It also signals oncoming traffic their lights are blinding. However, in some situations it is necessary to have both hands on the bars and brake levers. – gschenk Sep 16 '19 at 9:22
  • @mattnz sorry, for my previous reply. It does sound like a flimsy excuse. I did included the range of speed also for readers to qualify my statement in the light of my own behaviour. It is only fair you criticise me. However, someone with a dazzling light ought to consider that there may be riders who take greater risks than me. Even when the blame lies entirely at one's crash opponent, the expectation of something as inconvenient as smashing handlebars at 15 m/s combined speed might be incentive to re-consider one's lighting setup. – gschenk Sep 16 '19 at 9:33

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