Lights For Daylight Use
 

I want to upgrade my lights, both front and rear. My riding is limited to the daytime. How many lumens would I need to have good daylight visibility on sunny days?

You don't mention your riding environment.

Rural riding would tend to encourage brighter lighting than city due to the higher speeds and longer distances. Though of course that can vary based on the specific environment.

Trek/Bontrager sells a 100 lumen front labelled for city, and 200 lumen for other, so you could perhaps use that as guidance.

I do like the Ion 200 / Flare RT set - though I have a Trek bicycle and these work well with the Blendr mounts they have.

Whatever you settle on, please aim your front light correctly. Superbright headlights are all the new rage where I live. There are too many riders who aim their headlight up so that it shines into the eyes of oncoming riders on the bike path. (Who needs a headlight in broad daylight on a 4-mile bike path with no cross traffic?)

Pretend that you are riding at night and aim the light so it illuminates the road in front of you.
Brent

If you do require front lights please be respectful of others either use a proper StVZO light or make sure the beam is pointed towards the ground and for the love of all things good in this world don't flash unless you are in an absolute emergency situation and are trying to beckon for help. The rear is less dangerous as a flashing light but white light is very harmful to our eyes and despite what selfish people might say it isn't safer. I literally have to close my eyes or look away when these folks are passing and that is not safe for anyone.

I would highly recommend getting a dynamo as you will always have light as long as your wheel is moving and they generally are already StVZO complaint and you can get ones with USB charging or get a separate plug.

Here is a handy article about it from across the pond:
https://www.bikeradar.com/advice/buy...o-bike-lights/

You might also consider the Garmin Varia Radar rear light so you can get a little notice when a car is coming from behind and also give a little light as well!

For sunny days, blinking is still a great idea. Catch driver's attention early, and be visible when riding through mixed sun and shade. I'd want at least 200 lumens front, and 100 back.
I just went through checking on available lights with a co-rider looking to upgrade his sad, dim tail light. Not really bright and it was clipped onto his saddle bag, so it pointed way down, not useful.

I didn't like the compromises or design details from the other brands I looked at.

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I'm happy with my Cygolite lights for good mid-day visibility. And I really like the stretchy strap for the headlight. Rigid clamp mounts don't have a good spot on my bars.

Plugs fall out! I wish Cygolite would redesign their rubber USB plugs. They are tedious to plug in, and still can fall out and dangle on a ride. Not bad if its dry, but very annoying. I cut a rubber band from a cross section of a punctured inner tube, and wrap it around the body to cover the plug diagonally. That's secure, but fiddly to get it angled just right.

The Cygolite Dash 550 is now a 600. It's great in the daytime on their triple flash, and that's rated for 9 hours, I think. It has a bright LED reflector, and 4 small LED assist lights.

On dark bike trails, it can be set to just the 4 small assists on steady, and easily aimed downward to light the path and not dazzle oncoming riders. Nice! (There's also a 70 hour flash mode from the 4 small LEDs, which is fairly visible. But I always use the 9 hour very bright flash mode.) I like being able to aim the light up or down since the strap easily allows movement. And the strap has a nice left-right clicking swivel to point the light correctly on angled bars.

If I don't get home before dark, it runs about an hour on high, and that's a good "see the road ahead" light, not just a warning for oncoming drivers. Or click to steady medium and aim more downward.

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The Cygolite Hotshot Pro 150 is perfect for mid day. (now there's a 200 lumen version, which will be "somewhat" brighter than 150. Lumens have to just about double to look one step brighter.) I run the single flash mode, a sharp, brief 150 lumen blink. I use the other button to slow it to two flashes a second, or even 1 flash a second for an all-day ride. I think this is way more noticeable in bright light than the busy multiflash modes. I've instantly noticed other cyclists in my group a quarter mile up the road.

All but one mode is terrible for close group rides after sunset, and for bike trails, etc. The flashes can't be dimmed down, only slowed down in flashes per second. But the steady beam mode will dial way down to a reasonable light level.

At night, riding solo in traffic, I'll use the ramping up and down flash mode, a "waaa-waaa" effect. I think this is less annoying to driver than a short, sharp flash, and it looks different too!

The rigid clamp works fine for this taillight, and the light is secure on it. It appears there's a rubber strap version (that's a bit hard to find) that works with oval seatposts.

I loaned out my old Cygolite 2W tail light to another rider, and it's okay. Not as eye catching in daylight, but still helpful. I'm guessing it's 30-50 lumens at the most. I'm kind of surprised it still holds a charge after all these years. Good.

I have a 100 lumen blinking tail light and a 600 lumen up front that can be dimmed or blinking. I blink it during the day and run it on dim for the most part at night. When I'm not on the road and mixing it up with traffic, I shut off my front light. I'm not worried about other bikers, hikers, skateboarders or what have you seeing me, just vehicular traffic. I also don't aim it directly into oncoming traffic as that is just being obnoxious, yet most vehicles see it, especially at intersections. With my blinking up front my incidences of being cut off when I have the right of way is much lower. I still ride like I expect people to be stupid and self absorbed.

I think the best option for everybody is just wear bright flourescent yellow or flourescent orange helmet and shirt.

That stuff never fails to get attention of everyone on the road and you are visible from many miles away. Best of all, no lights to worry about.

Another option is just put bright flourescent colored tape on your helmet. Reflectorized bright flourescent tape even better so you remain visible late in the afternoon if you managed to stretch your ride unintentionally and you forgot to bring any lights.

I have a 700 lumen light I used when I was commuting. During the daylight hours, it is on flash and you will not miss seeing me. My tail light is 200 lumens and is also a flasher and very noticeable.

I like the Bontrager Ion 200 RT/Flare RT Light Set
and Lumintop B01 Bike Flashlight

Years ago, I got hit by a car rolling out of a rural church parking lot. (At very low speed, it just tipped me over and bent the back wheel. Only got a bruise.) I was wearing my hiviz long sleeve jersey.
Our attention is drawn to movement, like blinking lights.

I disagree. When driving, I notice a cyclist using lighting well before I notice one without, regardless of what they're wearing. My attention is drawn to blinking lights before steady lights.

IMO, blinking lights > steady lights > fluorescent/bright clothing > black/grey/dark blue clothing

As far as the OP's question - sorry, I don't have a good feel for visibility in terms of numbers of lumens. Most daytime running lights I've seen cyclists use seem pretty effective to me, so I think you're OK going with any light recommended by a major manufacturer (Lezyne, Cateye, Cygolite, Blackburn, Dinotte, Nightrider, etc.) for daytime visibility. Perhaps brighter is better, I'd base my decision on affordability at that point.

I mostly ride in traffic, and like to put medium powered flashers on my helmet, so they're up high where they can be seen more easily.
https://cimg4.ibsrv.net/gimg/bikefor...68db976a54.jpg

Another aspect of flashing vs steady is that you'll get longer run time when flashing. However, laws vary as to lighting so best to check.

IMHO there's a balance between bright enough to help you be noticed yet not so bright that you adversely impact others.

Here's an article worth reading through: https://www.bikeradar.com/advice/buy...g-bike-lights/

There is shockingly little test data on such things, but - from what little is available - this is correct. On the flip side, it is easier to judge distance from a steady light. So, in high-traffic areas, it might be smart to use a flashing taillight AND a one with a steady beam. I don't like using a wildly flashing light, though, so my compromise is to run a Cygolite which has an unusual mode: the light gradually lights up and gets brighter, then dims down to nothing, then repeats. It's sort of a very gentle flash, and the speed/frequency is adjustable.

Or brightly colored shoes/socks which move a lot.

The truth is, in broad daylight, you need a LOT of lumens. I am running a 500lumen light up front and in broad daylight it's still not all that visible. Same with the 250 lumen tail light I use.

Blinking lights yes. But steady lights doesn't seem to make a difference unless it's shining directly into the driver's eyes (not a good idea also).

During WW2, the Allies tried to experiment making planes less visible during daytime from the ground via "active camouflage system" - a very primitive version of the ones we see in movies.

Guess what? The solution was to put steady lights of medium brightness (same color) all over the plane's skin. Where the plane's skin is not illuminated by the sun or shadowed by parts of the plane, lights on that part are turned on. Initially, controlling the lights were made manually but would eventually be automated using early photovoltaic cell devices. Ironically, the experiments proved the system was successful in making the plane less visible from ground observers.

I'm not saying that lights are useless or would make things worse (in most cases, it's a good thing for daytime use). Just sharing a fun fact that lights when used in a certain environment like aircraft during daytime can also make it less visible.

For bikes, the light needs to be considerably brighter than the background if to be used to make you more visible.

The roads I ride on have 2.5-4 lanes - 1.5-2 lanes for traffic, and 1 or 2 for parking. Drivers who can see my flashing white light before passing me are driving in the direction opposite from mine, and they're in a lane that's pretty far from mine. The flashing light simply does not protect me against a collision with those cars. How wide are the roads you users of lights ride on? Do you really think the lights will prevent the drivers who can actually see your lights from hitting you?

Sure, drivers who pass you might see your light in their rear-view mirrors, but they're already ahead of you then, and you control whether or not to collide with them..

If you're driving your car and exiting a parking lot or entering one via a left turn, is it not highly possible that a flashing light is easier to ignore than a steady light? After all, the flash could be viewed as anomalous, an optical illusion.

Now, I confess to wanting to ride in the Northbound lane of a bike path or MUP when a Southbound rider is flashing his blinding light into my eyes. I don't, but I want to to anything to get that f__ing light out of my eyes. So far, I've always concluded that I'll get away from the light faster if I stay in my lane than if I alter course.

The only research I've seen is from England several years ago. That study concluded that something visible and moving, like reflective socks, was the best way to get drivers to give a rider space, but that was just one study.

Drivers always gave me a lot of space when my bike wore a small orange flag sticking out from my rear rack horizontally about 18". Drivers never came close to me when my bike sported that flag. Alas, the flag did not succeed in the marketplace, and I could not replace it after mine broke.

One thing I have only recently noticed is that lights can be a very good idea on rural roads. In the Summer there can be a large change in ambient light between full sun and the deep shade of mature trees over a low traffic road. Without a light, a cyclist in the shade can be nearly invisible to a motorist in the full sun, and, of course, the lightly travelled road is just where the motorist is expecting little or no other traffic. Paradoxically, a bright, clear day makes it hard to see a cyclist.

I found this study on kit and lighting very “illuminating” since I thought I had a pretty firm grasp on what constitutes good visibility. Reading this I learned a couple of interesting factoids I will adopt.

https://www.roadbikerider.com/incisi...visibility-d3/

The writer seems to be misinterpreting the results of that study. From the article:Note that the study didn't show that bright jerseys were no more visible than dark jerseys. The study simply shows that bright jersey doesn't make you look like a cyclist if you are not moving. If you are moving, then I am sure the results would be very different.

It’s nice to cherry-pick where you disagree but you failed to point out that either placing lights or brightly colored apparel on your legs or shoes is very good at drawing attention. This may be a big DUH to you but to others that implement their suggestions just might save their life.

I have zero disagreement with that part of the article.
I just don't want people to come away from the article thinking, I'll keep wearing my dark jersey because bright jerseys don't do anything anyways.

Having an excellent run with Cygolites. On the back a 150 Pro can be seen (in my Third Eye visor mirror) flashing off signs over a block away. On the front, both a bar mounted Metro 360, later replaced with a Metro 600, did not get the attention of motorists in any mode, especially in low to night conditions. My theory is that the lights faded into the background lighting of other cars, street lights and house lighting. When either is mounted to the top of my helmet, it is a different game with most cars dimming their brights. In my regular, semi-upright, riding mode the light is tilted to illuminate the street/path so I can see any holes or obstacles. At the same time, I can tilt my head up to get attention if necessary. I prefer the almost continuous, triple stutter mode in darker conditons (Metro 600) with the nearly motorists' headlight lumens. The 360, on flasher mode, is good for the day hours. Even more than driving selfishly, a motorist needs something attention grabbing... too much distracting them within the cockpit!

I agree that, other things equal, a brightly-colored jersey is more desirable. But if you have a good blinkie light, I'm not convinced that the jersey color matters much at all.