Lights: how bright is too bright?

[Wheeledweenie]

The other night on my way home I looked behind me before pulling out round a parked car and was dazzled by a cyclist's light that was so bright it left black spots in front of my eyes. Luckily the traffic wasn't heavy but it got me thinking. It's not the first time it's happened and it's deeply unpleasant. I'm talking about lights that are above and beyond car headlights.

I've definitely seen an increase on my commute (west London) in seriously bright lights on some bikes. Of course people should have lights on their bikes and in isolated areas you may well need ones bright enough to light your way but how bright do they need to be in cities with street lighting?

 

[summerdays]

I'm not sure its how bright - but the angle that they are shining at. I've been making sure my new Hope 1 is pointing down at the road in front of me - although I admit I've yet to lean it against a fence and then see what it looks like from a distance.

 

[Wheeledweenie]

Good point, perhaps it's the angle they're at.

 

[HelenD123]

I'm not sure its how bright - but the angle that they are shining at. I've been making sure my new Hope 1 is pointing down at the road in front of me - although I admit I've yet to lean it against a fence and then see what it looks like from a distance.

+1 I've just got the Hope Vision 1 and there's a warning not to look directly at the light. It got me thinking that car headlights are lower down than handlebar-mounted bike lights so I'm going to have to be very careful to angle it down. I'd be doing that anyway to better light up the road.

 

[Bollo]

It's an unfortunate side effect of the vast improvement in cycle light technology over the past couple of years. If the lights are just there to be seen, pumping out more lumens is a pretty crude way of doing it as the size of the light aperture or lens, the beam distribution and any flashing function will all have a large effect.

If you need lights to see along unlit, crap surfaced country lanes at night and ride at a reasonable pace, then you've got to pump out a reasonable amount of light. This is likely to be more or less dazzling if left on 'full beam'. If that's the case, then I usually drop the power to my main light if another vehicle is approaching. The last thing you want is a dazzled driver heading your way.

 

[Davidc]

Not as bright as the Hope 1 but I'm using a Cyo 60, and if that gets knocked so it's in driver's faces I get complaints.

It doesn't take 60 or 120 lumens to be seen - these lights are for seeing, otherwise they just dazzle which puts everyone at risk. They need to be aimed at the road ahead. B&M reckon on the centre of the bright beam hitting the ground 10m from the bike.

 

[beanzontoast]

Out of interest, and in keeping with the OP's theme, how many lumens should a decent light be for 'being seen' rather then 'seeing with'? What's do people see as the benchmark level?

 

[Norm]

I have two front lights.

The more powerful Exposure Maxx is bike-mounted and is used on low power or flash whenever I'm on the road. The lack of proper beam distribution means it shouldn't be used on high power when other vehicles are around. Although it does get cars to dip their own headlights before they come round a corner, so it must appear as powerful as a car headlight. It is nearly always on flash setting, though, and set to point at the ground about 10m in front of me.

I also have a head mounted Exposure Joystick, which is usually on low power on the roads. That is enough to make sure I get noticed by a car coming out of a side turning, although on low power, it doesn't cause much discomfort. On high power, though, it is blinding to anything within about 30m.

Tests were done on Mrs Norm, BTW, rather than just flashing my torch at random motorists and then asking what they thought.

If it is just to be seen, you could use a £10 Cateye.

 

[Wheeledweenie]

Out of interest, and in keeping with the OP's theme, how many lumens should a decent light be for 'being seen' rather then 'seeing with'? What's do people see as the benchmark level?

I have bog standard Cateyes and, for me, I reckon it's enough as practically all of my commute's on the Uxbridge Road, which is lit all the way but I just waed to know others' views as some of the boys near me seem, in my view, to be getting a bit excessive on sheer brightness.

 

[summerdays]

I hadn't bothered with upgrading my lights until this winter when I was having to cycle a very poorly lit road with a poor road surface - hence why I want the light pointing downwards anyway.

Now I've got it I'm smitten

 

[beanzontoast]

I have bog standard Cateyes and, for me, I reckon it's enough as practically all of my commute's on the Uxbridge Road, which is lit all the way but I just waed to know others' views as some of the boys near me seem, in my view, to be getting a bit excessive on sheer brightness.

I've noticed more people using brighter lights too, and that's in the space of last winter compared to this. I guess as long as it's not going to dazzle people, the brighter, the better - though in my case I also find using two Smart/Cateye lights front and back also works well.

 

[tyred]

I think everyone needs to make their own assessment of their own lights by sitting in a car and getting someone else to ride the bike towards you, preferably on an unlit road.

 

[Norm]

I think everyone needs to make their own assessment of their own lights by sitting in a car and getting someone else to ride the bike towards you, preferably on an unlit road.

I'll have to say that I think that is a great idea, because that is pretty much exactly what I did. :troll:

I pulled into the stables where The Smalls were having their riding lesson and the wife thought it was one of the horse transporters coming into the yard, there was that much light as I rode up to her. (That was intentional, I had the whole lot on full to see what her reaction would be)

Let's just say that she doesn't worry about me not being seen at night any more.

 

[BentMikey]

When I arrive in the park at night, my friends often comment how they're not sure if it's me or someone in a car.

 

[Browser]

Echoing what Bollo said, there are a lot of lights pumping out big lumen figures, but it's not really well-directed. I suspect that most of the very bright lights (500L and upwards) are really only intended for off-road use and just have clear or translucent front covers. Vehicle lights have quite complex lensing arrangements, so that the driver can see where they are going, the oncoming traffic isn't blinded and they incorporate features like a 'kicker' in the nearside light to help illuminate pedestrians on pavements.
I am going to investigate either fitting a shroud around my light or a small motorcycle/scooter lens over the light unit to try and cut down the dazzle, as there is a lot of spilled light being wasted and compromising oncoming drivers' vision.
Beanzontoast, it all depends what the illumination state of the roads/paths/tracks your ride on is. If you are all on city roads, a Cateye commuter light will do as you probably don't need to see the road surface, if all of the streetlights work.
commute in on unlit rural roads and have established that much less than 300 lumens leaves you blind. The Ayup V Twin Sports puts out 400 lumens, my Niteflux Enduro 8 puts out 540 lumens and I still sometimes feel I could do with a bit more.