TimothyH

I don't believe there is a practical limit to brightness as long as the beam is shaped and aimed properly.

Motor vehicle headlights drown out my bike lights as they approach from the rear. 1850 lumens on my bike is inconsequential compared to the thousands of lumens put out by modern automotive systems as a car passes.

It is certainly possible to buy a bicycle lighting system which overpowers automotive headlamps but this thread asked about practicality, not possiblity. Most would not consider such a system practical from either a cost or form factor standpoint.

Running 2000 lumens would be possible for under $250 - two Light & Motion Urban 1000 lights, one on the bar and another on the helmet. This is probably close to what many would consider the practical limit and the vast majority of automotive systems are much brighter. Certainly the OP's 700 lumen light is nowhere near the practical limit.

-Tim-

dmanthree

I don't night ride any longer, so I only need a light to be seen during the day. I use a NiteRider Lumina 850 as a flasher. Small, light, mounts easily below the computer, and it's very visible, even in daylight. Why not?

canklecat

Depends on the beam pattern. I'm comfortable with around 300 lumens for most riding. 500 is better for rural rides. More power is better because you can get longer run times at low or medium output. On the MUP and casual group rides I usually run low so pretty much any light is good for a few hours.

And I use various beam cutoff doodads on the MUP to avoid blinding other folks. One is a homebrewed hood for my Light & Motion Urban 500. And the handlebar bag on my hybrid cuts off the beam for my headtube-mounted headlight, which is handy for casual rides on the MUP at night, coming home from errands, etc.

My lights range from barely adequate 255 lumens to 750 NiteRider Micro. I'm about to add an 800-1000 or brighter light just to have longer runtime at lower output. The NiteRider 750 Micro is pretty good, fine for errands or one-hour rural workout rides at full output, but has a small battery, short runtime, and dims gradually so the rated 750 lumens is good for only a few minutes. By the time I'm at half charge it's down to around 300 lumens or less. In contrast the Light & Motion Urban 500 retains most of its maximum output until the battery is depleted. But some larger NiteRiders have better discharge characteristics.

For taillights, depends on day or night time rides. I usually run moderate power taillights for nighttime. But I just got a Cygolite Hotshot 150 for daytime use. My 3 mile rides to twice weekly physical therapy includes 400 yards of the most dangerous street I routinely encounter. Just a bad confluence of merging traffic due to a boulevard and surrounding highways. But there's no better route to my PT clinic. The Hotshots don't have a wide beam but are stupid bright, almost painful, when viewed from directly behind. Hopefully that will instinctively nudge any tailgator off my rear. 99.99% of drivers are fine, but about once a week some jackass gives me grief on that ride, tailgating or brush-by passing -- assuming they're even looking at the road instead of their phones. Not that any light can cure that problem.

To be seen better, I almost always run helmet lights. Just switched to a pair of smaller, lightweight and flat Blackburns, including one white strobe that's almost annoying to me and I'm behind it. But I can definitely see drivers reacting at night. It's not blindingly bright but that strobe is annoying as hell.

seamuis

I commute at night. I run two wide beam 1500 lumen lights with diffusers, so 3000 lumens total output. Wouldn’t consider for a single second, riding with anything less. In fact, I’d be happy to add to those total lumens. Of course the Lux measurement isn’t the same, and I’m not sure what it is off the top of my head, but it is a more practical measurement. Each light has about an hour and a half runtime, but has hot-swappable batteries, so I can add to the total runtime by carrying a couple spares. My commute time is on average about 30 min. though, so it’s more than enough.

rm -rf

My 2000 lumen Dinotte has a very wide, very smooth beam. No hotspots. I run it at full power in the city, where there are bright car headlights and alternating brightly lit and dim areas of the streets. It's way too bright for dark country roads, I'll use the 25% 500 lumen setting at speeds less that 15-17 mph, click to brighter settings where my speed increases. Reflective road signs are blinding at 2000 lumens!

~~~
Doubling the lumens makes the light "somewhat" brighter, not "twice as bright" to your eye.

I posted in a 2018 thread:

The difference to your eye between 750 and 1000 is fairly subtle. The 750 should work.


Helmet mounts
I had a 200 (actual) lumen light, back when those were considered very bright. It was okay for riding under 15 mph, but gave very little warning at higher speeds. So I added an LED flashlight of 180 lumens on my helmet.
Advantages: seeing around a corner, very nice. Blasting a barking dog in the eyes, it backed off.
Disadvantages: I wanted to keep my head steady, so that the beam would normally point down the road. The narrow flashlight beam projected farther than the bike light. But that was hard on my neck! And in group rides, I had to be careful not to look at another rider.


Beam patterns
Some lights have a narrower beam that projects farther down the road for the same lumens. But these tend to have a sharper cutoff at the sides, which is kind of distracting to me.

I have a very bright light with a wide, smooth beam. So it lights up the whole width of the road, and the sides, too. I go full power in the city, to compete with car headlights and make a bright pool of light on the road. In the country, that's way too bright -- reflective signs are extremely bright.

Group rides at night
Like another post mentioned, bright lights behind a rider cast distracting, moving shadows in front of the rider. I put my light on the lowest setting, and aim it downwards. Each rider in a group just needs to light up the road directly in front of their wheel, then the whole group can see. So a light that can pivot downwards while riding is useful.

And the newest rear blinkies are way too bright for a group. Mine has a non-blink, dim mode.

jlockwood98

This is an important point. The "high" setting on many lights is sometimes only good for an hour or so. I buy lights based on their output at the medium and low level, where I can get several hours of use.

TimothyH

What brand/model are you running?


-Tim-

MEversbergII

Some good experiences / advice between that thread and this.

I was unawares of the Light and Motion brand - they might be worth checking out.

For the moment, my Metro 700 is sufficient, but I might take the avenue of buying a brighter light model and running it lower so I have longer duration (and the option for more brightness should I feel I need it). The Metro 700 may in that case migrate up to my helmet - I had been thinking about giving helmet lights a try anyways, so I might pick up a helmet mount here shortly regardless.

DomaneS5

I have 750 and 900 lumen Niterider lights. I can't tell the difference. Both are more than adequate for pre-dawn rides.

TimothyH

Light & Motion Urban 800 - $48
https://www.excelsports.com/main.asp?page=8&description=Urban+900&vendorCode=LIGHTNMO&major=3&minor=6

One can easily get three hours runtime by using low power settings when full brightness is not needed - climbing hills, familiar roads with no traffic, etc.

Don't remove the light from the rubber mount as some have reported that the tab on the light can break off. Instead remove the rubber mount with the light. Its easier to do that anyway.

It also comes with a GoPro mount which I find most convenient for mounting under a GPS.

Beam pattern is the best I have seen.


-Tim-

Leisesturm

I kind of agree. However I mount the other light on my helmet. I am personally quite night blind and it is VERY useful to be able to shine 800 lumens (claimed) around corners and into dark crevices that a bar mounted light no matter how bright simply will not reach. In Portland, OR where the cycling community is very large and comprised mainly of Millenial tech savvy up and comers. Cycling in the early dawn against the flow of inbound bike commuters is a study in headlight diversity. I would estimate the dual light users at ~10%, but of that, 90% have the extra light on their helmet.

MEversbergII

Yep, at 60 minutes the 700 was tested to start dropping (rapidly) below 700 lumens: We Test Lights | Metro 700 Test and Review

By that example, anyways.

Speaking of mounting lights under the bars, are there any generic clamps that fit Cygolite headlights but use screws instead of a knob to tighten them? If I mount mine upside-down it's likely to interfere with my handlebar bag.

no motor?

I did that for years for under $100. I had a Magicshine with a diffuse lens on the bars and a C8 flashlight on my helmet that were rated at 1,000 lumens each. I'm not sure how many lumens they actually put out, but it was enough for me. I also used a Vis 360 on my helmet too, mainly for the rear light and there lumen estimates were way more conservative than the other lights.

road292

Standard Halogen automobile low beams are somewhere in the 1500-2000 lumen range each, so maybe 3000-4000 lumens total for the usual two at the front of the car. I'd suggest the reason they seem to "drown out" your bike lights certainly includes the 3-4x more lumens, but is in no small part also because, properly installed, they are aimed well and have a good cutoff pattern to direct the light where it's needed.

MikeyMK

High brightness isn't ideal, as eyes adapt and can only cope with a narrow range.

Some people make the mistake of having blinding main beams on their car, then wonder why they can't see a thing when they have to dip them...
Better to just have a good dipped beam that projects enough to not need to use mains.

Same with bikes in a way, because too much light in the centre foreground makes it harder to see everywhere else. Far better to have good scatter, so the light isn't as intense but travels further.

cyccommute 

I'm not sure how you mount lights upside down on a bike with a handlebar bag to begin with. Seems the bag would interfere with the lights no matter what. That said, I use Marwi clamps for my lights. It only took a little ingenuity to convert the mount for a Cygolite to Marwi clamp. This is the result (sorry I don't have a better picture)

DSCN0308 by Stuart Black, on Flickr

I just leave the clamp on the bar all year long. Here's what that part of the clamp looks like.

DSCN0378 by Stuart Black, on Flickr

It's fairly low profile and could easily be mounted upside down.

cyccommute 

Somewhat true but incorrect. Eyes do indeed adapt to light but the rod photoreceptors in your eye that allow you to see without lights become "bleached" upon exposure to just about any white light. The rods contain more photopigment but it is slow to respond after it has been "bleached" (i.e. exposed to light). It takes roughly 30 minutes of continuous dark for the rods to return to the ground state. In other words, they are very sensitive but easily overwhelmed. Astronomers (amateur and professional) use (weak) red lights to illuminate their area at night to avoid bleaching out the rods.

This is just wrong. Once you've turned on a light, your vision outside of that beam of light is shot...see above. A more intense light doesn't have much effect on the cone photoreceptors which are less sensitive and recover more quickly. High beams or low beams on a car won't make much difference. The high beams just illuminate further down the road. Your night vision is already shot.

Nope. Try an experiment. Walk (or ride) across a dark field with a light of some kind at night...any light will do. In the middle of the field, turn off the light and try to walk back. You basically won't be able to see anything for quite a while. Do the same thing but wait 30 minutes before you start back, you'll be able to see a whole lot more. I've often experienced this while camping in dark sky areas. In the middle of a moonless night, with just star light, I can walk around without problem. I might even be able to ride a bike. But if I happen to snap on a light, I can't walk anywhere for a long time.

Bottom line, once you've turned on a light, your "night vision" is "night blindness".

cyccommute 

I fully agree. My lights, however, have gotten a little dimmer as we've moved towards LED. For light output, I've found nothing that compares to an overvolted MR13 halogen light. Running a 12V MR13 at 14.4V puts out a whopping...and real... 1200 lumens per lamp. It's enough that I could illuminate trees 1/2 mile away across a lake. LED bicycle lights don't put out nearly that amount of light and, for some reason, their throw isn't a long. On the downside, they pull a lot of power.

MEversbergII

Cheers; my bag actually mounts in towards the rider: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I like the look of those cam-locks better than the threading my current light mount has. It's minor details, though. Is that bar mount one of their products? Didn't spot it on their site - clever, though (I assume this causes no issue with getting the headset tight?).

gnappi

Riding on pitch black blacktop in sparsely lit suburban streets with a number of vermin, pot holes and debris... brighter light is better.

The problem with LED lights is the brightness "claims" which are much like the amp hour ratings of the batteries of which both are wayyy over inflated.

What's most important to me are the brightness / control features and cell it works with.

My light uses a single 26650 cell, has 4 brightness settings (with last set brightness memory) as well as a flash mode if held on. The 26650 has higher Ah rating than AA or 18650's and if I forget to recharge for a couple of nights it's no biggie.

Retro Grouch 

I bought a very bright tail light that I think is pretty much useless because it it so small. A very bright pinprick. Utterly useless in daylight.

Is there a specification I should be looking for that somehow combines brightness and size?

cyccommute 

That clears it up.

By the bar mount, I think you mean the extender that I have the clamp mounted on. If so, no, EL-34 doesn't sell those. Velo Orange does, however. It's the Dajia accessory mount. You can either order it direct or you can get it from a local bike shop through Quality Bicycle Products (usually referred to as QBP). It's about $15 and replaces two of the bolts in your stem. Of course that means that you have to have a stem with a 4 bolt face plate.

It works really well and is a very solid mount for lights.

MikeyMK

Later...

So you disagree, then reflect precisely the same point on an exaggerated level that I never referred to at any point. Ok then..

In summary, differences of light in any way will hinder overall visibility somewhere. Whether that be switching from one brightness to another, or having two different brightnesses in the same field of vision.

Far better to have a light that fills everywhere you need to see at a level that is as sustainable as possible throughout your journey.

At least, in the few decades of experience with my own sight.

cyccommute 

Although I don’t agree completely with rm -rf’s point on not being able to tell the difference between 700 and 1000 lumens, he does have a point. From a physiological stand point, the way the human eye responds to that difference is fairly narrow. Even larger difference, say 300 lumens to 1500 lumens are going to result in the bleaching of the rod cells and, thus, a complete reliance on cone cells which respond much quicker to light differences. You aren’t going to see any differently outside of the light you are using because the light is dimmer than if it is brighter.

Bottom line: you can’t preserve night vision...which is what you are talking about...by using dimmer lights. You can preserve it by using the red spectrum of light but any white light photons of any intensity bleaches out your night vision. Using a dimmer light just means that you won’t see as much.

Again, try the experiment and see how it works. I, too, have many decades of experience with riding at night. I know, from experience, that using dimmer lights doesn’t make riding at night easier or better.

roundrocktom

Bontrager Ion Pro RT/Flare RT Light Set. Expensive gift, but well appreciated.
Those HIGH settings are perfect to bright Texas sunlight. I use the strobe pattern during sunlight hours.
They have a lower power setting for the night either on or strobe. I use low intensity on at night — no need to blind traffic.
Neighbor rode his handcycle at night with high-intensity strobe. Oh, it would give me a headache when I passed the opposite direction. I had to come to a stop and let him pass. Not good.
For aircraft preflight, at night I have red flashlights. You can see fine; red cockpit lighting helped preserve night flying eyesight. On the bicycle, I want white lights, so others know I am approaching.