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Old 12-30-08, 12:14 PM   #1
Zomar
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Rear Light Theory

Suppose I have 3 blinky lights:
-2 Planet Bike Superflash rear light (http://ecom1.planetbike.com/3034_1.html)
-1 Planet Bike Blinky "7" rear light (http://ecom1.planetbike.com/3019.html)

..and I am uncertain what is the best way to set them up.

The "7" is supposed to be well visible from the side. I haven't compared it to the Superflash yet ((I don't have them yet, but I will soon) from the side, but ). I think that the "7" is more visible when viewing it from an angle since that is how it's marketed.

The "superflashes" have a brighter and more eye catching illumination.

Two things to consider: position and mode.

1. I was thinking of putting one on the back of my helmet, one on the back of my rack, and one on my seat post. (feel free to suggest other setups)

2. Each light has the option of blinking or solid illumination.

Taking these two things into consideration, how would you position the lights, and what modes would you set them too if safety from cars is the main concern. I will be riding primarily in the dark and around sunrise. The streets have streetlights but are still rather dark.

Last edited by Zomar; 12-30-08 at 12:18 PM.
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Old 12-30-08, 12:28 PM   #2
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I am thinking ... the more lights the better any way you want to look at it.

I ride in the dark every day too.
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Old 12-30-08, 12:37 PM   #3
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How about one PBSF on your helmet (blinking), the other on your rack (blinking), and the Blinky 7 on your seatpost (solid)? And be sure to pair it with reflective gear, especially the ankle bands (movement really catches drivers' eyes).
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Old 12-30-08, 01:08 PM   #4
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I suggest the PBSFs blinking on opposite cycles of each other. You'll get a superbright LED flash twice as often. To get a good rhythm between the two lights, you first need to determine the length of one flash cycle. Turn a light on flash, and watch the pattern until you can count with the main flash of the light (like in music, 1, 2, 3, 4...1, 2, 3, 4, etc). Now that you have the tempo down. Start one light and then start the other light halfway between beat 1 and 2 (an eighth note if you will), and you'll pretty much have the LEDs flashing opposite of each other.

It's harder to accomplish this is you turn one light on, watch it for a while, and then turn on the other light. This is because there is a delay in the circuitry, so the light doesn't start flashing right away when you press the button.
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Old 12-30-08, 03:10 PM   #5
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Is a solid light necessary? I usually kept both my PBSF (seatpost, right below the seat) and my dealextreme $3 blinky (on my bag) on flash mode because I figure once drivers know there's a bike there, it shouldn't be too hard to notice the retroreflectors.

Even if those somehow don't reflect (i'm assuming this is rare, especially given the multitude of angles I've covered) they should still be able to make out a semi-accurate distance gauging from their headlights, streetlights or even moonlight assuming they're paying attention to the flashing lights.
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Old 12-30-08, 03:44 PM   #6
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Originally Posted by roja View Post
how about one pbsf on your helmet (blinking), the other on your rack (blinking), and the blinky 7 on your seatpost (solid)? And be sure to pair it with reflective gear, especially the ankle bands (movement really catches drivers' eyes).
+1
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Old 12-30-08, 04:09 PM   #7
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I mount one Superflash on the seatpost or rear rack. That guarantees me that it will be aimed where I intend it. I mounted a Blinky 7 on each seat stay facing slightly outward. I'd put the Blinky 7 on your helmet. It has a wider range of visibilty than the Superflash. I see flashing blinkies on other bikes easier when I'm driving, so that's what I set mine for.
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Old 12-30-08, 04:11 PM   #8
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I'm (almost) in your same situation, where I have 3 rear lights, 2 MARS 3.0's and 1 Superflash, and I clip the MAR's onto my shoes and put the Superflash on my seatpost and run all of them in solid.
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Old 12-30-08, 08:14 PM   #9
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I'm (almost) in your same situation, where I have 3 rear lights, 2 MARS 3.0's and 1 Superflash, and I clip the MAR's onto my shoes and put the Superflash on my seatpost and run all of them in solid.
The right answer, except the light on the seat post should be flashing. The rotating / up-down movement on the shoes, plus the flasher on the seat post should make even the densest driver notice.
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Old 12-30-08, 08:19 PM   #10
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PBSF on the seatpost, blinking, PBSF on the rear rack, solid, S7 on the helmet, solid.
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Old 12-30-08, 08:58 PM   #11
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Originally Posted by huhenio View Post
I am thinking ... the more lights the better any way you want to look at it.

I ride in the dark every day too.
I tend to disagree. There's a point where you become a distraction or spectacle. When drivers turn their heads to look the tend to drift in that direction. Not good. This is the reason HWY Patrol cars get sideswiped so often when making a stop.

As for the orig post I'd place the SF on your post and the 7 on your left seatstay. The third...where ever.
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Old 12-30-08, 09:24 PM   #12
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I use the PBSF on my backpack, which has a pocket area that it clips onto. I am thinking about buying the rack adapter to put it on the back of the rack. There is not room on my seat post because of the reflector that came installed on the bike.

I also have two cateye ld610's that I put on my panniers (axiom lasalle with straps for lights) or on each seat stay if I ride without the panniers.

I also have fenders with reflective tape going down the rear fender.

I have the PBSF set to blink and the ld610's on solid.
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Old 12-30-08, 09:25 PM   #13
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SuperFlash on the helmet (blinkie), the 7 on the seatpost (solid), and a SuperFlash on the rack (blinkie). That's the same setup I run.
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Old 12-30-08, 10:56 PM   #14
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Having read suggestions that motorists tend to ignore vertical objects more readily than horizontal ones, I would try mounting two blinkies as far apart as reasonable (say, 1/2 meter or 1.5 feet), perhaps on opposite ends of a very flexible pole mounted to the rear rack. Supplement these with a helmet light and a reflective vest. I also like reflective tape on the seat stays and cranks, as pictured earlier in this thread.
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Old 12-31-08, 02:23 AM   #15
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Quote:
Originally Posted by Pippin View Post
I tend to disagree. There's a point where you become a distraction or spectacle. When drivers turn their heads to look the tend to drift in that direction. Not good. This is the reason HWY Patrol cars get sideswiped so often when making a stop.
+1 Dead on statement. (No pun intended)
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Old 12-31-08, 03:18 AM   #16
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I have a Mars 3.0 on the back of my helmet, a Cateye TL-LD1000 on the seatpost and a Cateye TL-LD500 on the back of the rear rack. When I'm towing a trailer I may or may not forego the TL-LD500 on the rear rack, but I have a TL-LD500 on each rear corner of the trailer.

At night all of these lights are run steady on except one bank of the TL-LD1000 which is run flashing. I think flashing lights are a better attention gainer, but steady lights give better spacial awareness; as in it's much easier to judge distance to, closing speed and tell that the lights are moving.
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Old 12-31-08, 10:00 AM   #17
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Originally Posted by degnaw View Post
Even if those somehow don't reflect (i'm assuming this is rare, especially given the multitude of angles I've covered)
This may fall into the category of a job for Captain Obvious, but they'll only reflect if there's light shining on them, and that reflection will only be visible if the angle between the observer and the light that illuminates them is small.

There's a number of things that have to work out before reflectors are effective. By having lots of reflectors that point in all different angles, you've taken care of one of them, but all the other things are still in full effect. (Which is probably why you still use the blinkie, of course.)
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Old 12-31-08, 11:02 AM   #18
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Have them all on blinking. Spacial awareness is only a problem with strobe lights that give an instantaneous flash, blinking lights are fine. Seatpost ones can be obscure by things carried on the rear rack, so if your have a rack, the back of the seat is better. LEDs are very directional so if mounted on backpacks are visible only to passing aircraft.
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Old 12-31-08, 11:49 AM   #19
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I run a PBSF on flash on the top of my backpack. A Mars 3.0 in chase mode is on the bottom of my backpack. A second Mars 3.0 is on my seatpost in solid mode. Also have reflective tape on my rims and stays.

The PBSF is too directional for me to run as my only light.
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Old 12-31-08, 04:15 PM   #20
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I recommend against mounting blinkies on helmets or backpacks. Low-powered LED's (even the PBSF) are highly directional in nature...if they're not properly aimed they lose most of their effectiveness.

Better to mount them to seatpost or seat stay or rack, and aim them properly. BTW, Planet Bike sells a cheap mounting adapter that's compatible with most racks.
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Old 12-31-08, 04:18 PM   #21
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I recommend against mounting blinkies on helmets or backpacks. Low-powered LED's (even the PBSF) are highly directional in nature...if they're not properly aimed they lose most of their effectiveness.

Better to mount them to seatpost or seat stay or rack, and aim them properly. BTW, Planet Bike sells a cheap mounting adapter that's compatible with most racks.
I am with you.
I rode with two guys that had lights on the back packs even a PBSF.
They flop all the time and are useless on a back pack.
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Old 12-31-08, 05:13 PM   #22
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Originally Posted by Pippin View Post
I tend to disagree. There's a point where you become a distraction or spectacle. When drivers turn their heads to look the tend to drift in that direction. Not good. This is the reason HWY Patrol cars get sideswiped so often when making a stop.

As for the orig post I'd place the SF on your post and the 7 on your left seatstay. The third...where ever.
Out of interest is there any evidence to back this up? Has it actually happened to cyclists? I can see your point but I was wondering if and how often it happens.
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Old 12-31-08, 08:00 PM   #23
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Quote:
Originally Posted by Kerlenbach View Post
The right answer, except the light on the seat post should be flashing. The rotating / up-down movement on the shoes, plus the flasher on the seat post should make even the densest driver notice.
Take the lane. Even the densest motorist will notice, even if you have only the legal minimum of lights and reflectors.
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Old 12-31-08, 08:32 PM   #24
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Quote:
Originally Posted by Pippin View Post
I tend to disagree. There's a point where you become a distraction or spectacle. When drivers turn their heads to look the tend to drift in that direction. Not good. This is the reason HWY Patrol cars get sideswiped so often when making a stop.
Reference for this sideswiped problem? Reference for your alleged "reason" for this alleged problem?
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Old 12-31-08, 10:01 PM   #25
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Here's my theory. It may well be useless, I don't really know, but I offer it for what it's worth.

I usually use 3 taillights in the winter: helmet, belt clip, seatpost. The lower two I set to blink, on the theory that they are more on the level of car taillights, so blinking helps to set them apart from car taillights. The helmet I set to solid, since it is above the level of car taillights, and I have heard that a solid light is easier to track the movement of.

I also wear a hi-viz and reflective jacket, which I think is maybe equally important, as well as light-colored dress pants (for my casual-dress office).
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