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Inexpensive LUX meter from China to measure your bike lamp's output



 
 
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  #21  
Old February 23rd 18, 11:30 AM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 10,422
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Friday, February 23, 2018 at 1:19:33 AM UTC, AMuzi wrote:
On 2/22/2018 7:12 PM, Andre Jute wrote:
On Thursday, February 22, 2018 at 11:28:56 PM UTC, AMuzi wrote:
On 2/22/2018 5:09 PM, Andre Jute wrote:
On Thursday, February 22, 2018 at 4:35:07 PM UTC, Jeff Liebermann wrote:
On Wed, 21 Feb 2018 16:52:57 -0800 (PST), Andre Jute
wrote:

Even at such an attractive price, I'm not buying the meter, Jeff.

I consider it beneficial if those recommending a product would also
have some experience using it.

See my original post at the top of the thread, where I say, "No recommendation".

For health reasons, I no longer go for those middle watches of
the night rides, as no one will go with me and it's stupid for
me to ride alone on totally empty lanes. So I have nothing
to measure for.

I have a similar problem. I don't ride at night. Too dangerous
around here and my night vision is slowly deteriorating. However,
this has not stopped me from commenting on the topic and testing
various lights.

In any event, by subjective measurement a la Roger's post,
I judge I already have what on balance I consider BUMM's best
lamp, the first series Cyo R (I also have reflectorless
version but it isn't as good in lanes as the R, and I have
the Fly-E with supposedly the same optics but with a very
nasty hotspot), so I'm not even in the market for new lamps.

Et tu Jute? I was under the delusion

I don't know any engineers with enough imagination to suffer delusions. They stop at misapprehensions. If you want to see delusions in action on a mass scale, check the so-called "resistance" in your backyard. The difference is that a misapprehension can be corrected, but a delusion is a pathology that can at best be ameliorated.

that we were discussing
instruments and methods of measuring light output and not a review of
available products. Oddly, every time (and I do mean every time) I
bring up the subject of light measurement, the discussion immediately
drifts away from measurements and gets mired on the mud flats of
anecdotal experience and subjective "calculation". It would seem that
the participants greatly fear making measurements and the assignment
of numbers to their favored bicycle headlight, as if this would
somehow diminish the value of their illuminating experience. I wonder
if it is even possible to discuss light measurements without the
apparently incurable product endorsements, which incidentally is only
slightly less prevalent in the flashlight forums.

Oh, I don't back away from abstractions where relevant. But, on a "tech" conference with a predominantly American membership, what do you expect? Thoughtful hotrodders? Pull the other one.

I only need one tool. Anything within reach can be used as a hammer..

You and Clarkson both. I'm an intellectual: as a reflex, I reach for my trusty Pickett pocket slide rule. The saddle-leather slipcase is worn almost yellow, but I feel naked without it, and they don't make them like that any more, though my favorite everyday watch, which is decades younger, has a perfectly good rotary slide rule on its bezels as a backup:
http://coolmainpress.com/andrejutewatches.html#Navihawk

Andre Jute
God bless the instrument makers



You're right, The Resistance is a bunch of loons:
http://socialistresistance.org/brexi...e-goes-on/8534

And not just that one either!
https://www.theguardian.com/politics...dence-movement

Even those amiable Canadians went through their own:
http://mhs.mb.ca/docs/mb_history/29/...sistance.shtml



Gee, Andrew, I didn't even know about those. How depressing. Mind you, for Americans it is probably good news to discover they aren't the only nation to harbour a large hysterical and infantile, anti-democratic part of the total population.

Andre Jute
Fair to a fault


'resistance':

It's often quipped that if half the French who claimed to
resist the Vichy regime actually did, they would have won.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


One day after a good dinner on expenses I'm sitting in a bar in the West End with my editor of record, John Blackwell, and the designer of the Aston Martin DBS and V8, William Towns. These two jokers for a lark were massaging a Merlin V12 out of a Spitfire into Morris Minor. I was supposed to be interviewing them on the tab of another publisher for whom I was doing a car book, but I knew more about the engine than they did (I had eight of the Packard-built V1650s, which was a licensed Merlin design with more reliable bearings, for my offshore speedboats, and a dynomometer to develop them, and a couple of knowledgeable old chappies left over from the war to wield the wrenches and keep me from getting a conrod through the ribcage), so we were just getting nicely stewed at some absent party's expense. A middle-aged fellow from the bar follows me into the lavatory. When he just stands there eyeing me, I say, "Sport, I'm not queer, and I'm violent beyond your fondest imagination. **** off before you get hurt." This guy is aghast. "No, no, no!" he says. "I heard you're doing a book about one-off and small-production cars. I just want you to spell my name right when you mention that I designed the Austin-Healey 3000." Back at the table, when I tell them this, Bill Towns goes to the bar and brings back another guy. "Tell Andre who designed the Healey 3000." Promptly, the guy says, "I did." So I write down his name too. Bill lets a while pass, then goes to the bar and brings another guy. At the end of the evening, as they poured me out at the station to take the 0505 newspaper train to Cambridge, I had five names of guys who all swore blind that they designed the Healey 3000, all by their lonesomes. That was nothing. Bill told John after I was gone that he was once in company with six sole Healey designers. -- and there wasn't even a fistfight.

AJ
Ads
  #22  
Old February 23rd 18, 12:26 PM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 10,422
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Friday, February 23, 2018 at 4:14:39 AM UTC, Jeff Liebermann wrote:
On Thu, 22 Feb 2018 15:09:34 -0800 (PST), Andre Jute
wrote:

... I wonder
if it is even possible to discuss light measurements without the
apparently incurable product endorsements, which incidentally is only
slightly less prevalent in the flashlight forums.


Oh, I don't back away from abstractions where relevant.


No, but you do change the subject, divert the discussion, and
otherwise avoid the original topic, which involves measuring lumens,
and not psychobabble. At least you've demonstrated that I was correct
in suspecting that it is pathologically impossible to stay on topic.


It's my thread and I couldn't care less about policing it to stay on topic. Let a thousand flowers bloom.

I'm an intellectual: as a reflex, I reach for my trusty Pickett
pocket slide rule. The saddle-leather slipcase is worn almost yellow,
but I feel naked without it, and they don't make them like that
any more...


Yech. Pickett slide rules were awful. However, they did make some
specialized electronic and microwave slide rules, that I wouldn't mind
having. Basically, a cheat sheet on the back of the slide rule:
http://www.sliderulemuseum.com/Pickett/Pickett_N515-T_Electronic_CIE_DonatedbyAndyKeller.jpg
http://www.sliderulemuseum.com/Pickett.htm


Ooh, I wouldn't mind one of those electronic ones either, complete with the formulae printed on them!

I take it the paper slide rules in one of your links were given away as promotions. I'd pay for one from the Radio Relay League of America, or the RCA Schools.

Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


Here's my slide rule floating in space, a Pickett N600, the white one in the righthand piccie with Buzz Aldrin (the yellow one on the left that he took on another mission is the same, only in "eye-saver" yellow):
http://spaceflownartifacts.com/flown_sliderules.html
One wonders if Aldrin was allowed to take the saddle-leather case to the moon or if there was a cyclist with his little gramme scale saying "Tsch! Tsch!"

Andre Jute
When the going gets tough
  #23  
Old February 23rd 18, 05:28 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default Inexpensive LUX meter from China to measure your bike lamp'soutput

On 2/21/2018 12:21 AM, Jeff Liebermann wrote:

Also from several revious rants, if you draw a 1.13meter (44.5inch)
diameter circle on the wall, and shine your bicycle head light or
flashlight on the wall until it fills the circle, the lux meter will
read directly in lumens. It works because the area of the circle is 1
square-meter and:
1 lux = 1 lumen/sq-meter
If you light produces a non-circular spot on the wall or an uneven
pattern, just guess(tm) until you have a spot that looks roughly like
1 square-meter. No warranty for accuracy expressed or implied.


You need to build an integrating sphere.
http://forums.mtbr.com/lights-diy-do-yourself/diy-integrated-sphere-780122.html

Or buy one. http://www.pro-lite.co.uk/File/general_purpose_spheres.php

  #24  
Old February 23rd 18, 06:13 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Fri, 23 Feb 2018 03:26:25 -0800 (PST), Andre Jute
wrote:

I take it the paper slide rules in one of your links were given
away as promotions.


Yes. I used to attend various electronics trade shows. During the
1970's and 80's, it was quite common for vendor to give away such
calculators. Others came for ham fests, coworkers, and trash bins.

I'd pay for one from the Radio Relay League of America, or
the RCA Schools.


Sure. Pick out the one's you want and send me a shipping address.
Please leave me with the radiation, RF, and microwave calculators. The
rest, I don't need or use. You can also find a few on eBay:
https://www.ebay.com/sch/i.html?_nkw=paper+calculator+-roll+-rolls
or various collectors sites (which I can't seem to find right now).

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #25  
Old February 23rd 18, 08:32 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 4,018
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Fri, 23 Feb 2018 08:28:10 -0800, sms
wrote:

On 2/21/2018 12:21 AM, Jeff Liebermann wrote:

Also from several revious rants, if you draw a 1.13meter (44.5inch)
diameter circle on the wall, and shine your bicycle head light or
flashlight on the wall until it fills the circle, the lux meter will
read directly in lumens. It works because the area of the circle is 1
square-meter and:
1 lux = 1 lumen/sq-meter
If you light produces a non-circular spot on the wall or an uneven
pattern, just guess(tm) until you have a spot that looks roughly like
1 square-meter. No warranty for accuracy expressed or implied.


You need to build an integrating sphere.
http://forums.mtbr.com/lights-diy-do-yourself/diy-integrated-sphere-780122.html
Or buy one. http://www.pro-lite.co.uk/File/general_purpose_spheres.php


Did you happen to notice that they cost thousands and require an
expert to operate?
https://www.youtube.com/watch?v=mvyptpA-BmY (Light and Motion)
https://www.youtube.com/watch?v=11XrP51WzfE (Lezyne)

I built one from a paper mache newspaper ball. Something like this:
http://budgetlightforum.com/node/31356
It fell apart.

I also built an "integrating pipe" out of PVC plumbing parts.
https://www.youtube.com/watch?v=k2Dbmz8WXmE
Calibration and repeatability are problems.

The nice thing about an integrating sphere is that it works for most
any light source including light bulbs. Mine only works for
flashlights and headlights. Because of the lack of a well defined
pattern, my method won't work with bicycle tail lights.

What I'm trying to is give the average bicycle headlight buyer a way
to get a ballpark number for lumens produced. As long as the pattern
displayed on a wall is roughly circular, my method will produce a
tolerable approximation. The accuracy is lousy and considerable
guesswork is required, but in general, the results are amazingly close
to the manufacturers specs (when the manufacturer isn't fabricating
numbers).

Please note that I make no claims that a single number will provide
sufficient information for a comparison of lighting suitability,
superiority, performance, visibility, optimum pattern, etc.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #26  
Old February 23rd 18, 11:28 PM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 10,422
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Friday, February 23, 2018 at 7:32:33 PM UTC, Jeff Liebermann wrote:

Please note that I make no claims that a single number will provide
sufficient information for a comparison of lighting suitability,
superiority, performance, visibility, optimum pattern, etc.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


It's anyway pretty rare outside the pure sciences that a single measure of benefit or goodness (or badness) will tell you everything you need know. Practical applications just don't work like that.

Even graphs with a single measure over time are only "singular" for whatever appears on the other axis by the courtesy of assuming time is a constant, even though we've accepted since 1905 that time is a variable like any other.

I'm used to working with huge, expensive statistical studies at the interface of demographics and motivational psychology, to be used in making decisions that will cost (or lose) millions, sometimes billions -- I used to dramatize the risk of carelessness for my people as the number of jobs lost. From a strictly mathematical, theoretical statistical viewpoint, the number of assumptions and guesstimates from experience one is required to make even in a well-studied field can be disturbing, even discouraging to the newbie until he discovers that applied statistics is an art form for high rollers and the super-confident. It's this background that leads me to welcome a meaningful, simplifying, summing shortcut like your square-meter equivalent circle. Together with the distance at which the light from the lamp fills the circle and simple, well-known science, in this case the inverse square root law, it can let you estimate both the spread and the intensity of a properly designed lamp at distances useful to a bicyclist. Pity it won't tell you about the hotspots as well, or nearfield spill from the thickness of the lens, but then you can't have everything.

Yo, Scharfie: I liked the integrating sphere until I discovered you need a guy in a white coat to operate it. I'm allergic to men in white coats: simply too much experience of ticket-punched railroad minds telling me what I can't do, and expecting to be paid after I did it myself. Men in white coats are never worth the rise in blood pressure that accompanies their advent.

Andre Jute
Women in white coats are an altogether different matter
  #27  
Old February 24th 18, 01:15 AM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 10,422
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Friday, February 23, 2018 at 5:13:54 PM UTC, Jeff Liebermann wrote:
On Fri, 23 Feb 2018 03:26:25 -0800 (PST), Andre Jute
wrote:

I take it the paper slide rules in one of your links were given
away as promotions.


Yes. I used to attend various electronics trade shows. During the
1970's and 80's, it was quite common for vendor to give away such
calculators. Others came for ham fests, coworkers, and trash bins.


It wasn't until the 90s that I took up electronics because my mates at HP and European and Japanese equivalents had risen too high in management to have time to build what I wanted.

I'd pay for one from the Radio Relay League of America, or
the RCA Schools.


Sure. Pick out the one's you want and send me a shipping address.
Please leave me with the radiation, RF, and microwave calculators. The
rest, I don't need or use. You can also find a few on eBay:
https://www.ebay.com/sch/i.html?_nkw=paper+calculator+-roll+-rolls
or various collectors sites (which I can't seem to find right now).


Very generous of you, Jeff, but I wouldn't dream of breaking up your collection on an idle whim. I just wanted those two because I admire the institutions (1); I wasn't actually going to use them because a) I have my cheat sheet written into a convenient Excel spreadsheet of a complete transfer formula I developed (2) and b) I'd already decided to buy the Picket N515-T (the one dedicated to electronics) which you referred to in your earlier post with all those fascinating links; the 515 is so common on Ebay that if I'm patient I'll probably be able to get an NOS or pretty pristine used one.

(1) see the first pic as you scroll down the chapter at http://www.audio-talk.co.uk/fiultra/...dre%20Jute.htm

(2) http://www.audio-talk.co.uk/fiultra/...dre%20Jute.htm

Andre Jute
The kindness of strangers



  #28  
Old February 25th 18, 04:10 AM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 4,018
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Fri, 23 Feb 2018 14:28:26 -0800 (PST), Andre Jute
wrote:

On Friday, February 23, 2018 at 7:32:33 PM UTC, Jeff Liebermann wrote:

Please note that I make no claims that a single number will provide
sufficient information for a comparison of lighting suitability,
superiority, performance, visibility, optimum pattern, etc.


It's anyway pretty rare outside the pure sciences that a single
measure of benefit or goodness (or badness) will tell you
everything you need know. Practical applications just don't
work like that.


That's easy to remedy. Permit me to introduce my "Index of
Conformity(tm)" which measures how well someone agrees with my
reference opinion, which I hereby declare to be optimum and a de facto
standard. 100 is total agreement and 0 is total disagreement. By
comparing your prejudices, biases, impressions, and premature
conclusions with my optimum reference standard, as single number can
be used to measure your conformity to my ideal. For example, if you
were to purchase or build a bicycle lighting system exactly like mine:
http://www.learnbydestroying.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html
your system would be rated at 100. Any variations from this will
result in a lower score.

Even graphs with a single measure over time are only "singular"
for whatever appears on the other axis by the courtesy of assuming
time is a constant, even though we've accepted since 1905 that
time is a variable like any other.


I think it's safe to assume that bicycles will never achieve
relativistic speeds. Questions of time dilation, time travel, and
causality should not enter into the discussion.

Incidentally, "time is natures way of keeping everything from
happening at once". I forgot from whom I stole that. Unfortunately,
that didn't happen on Friday, when just about everything I attempted
failed badly and I was forced to work until midnight, subsisting on
half a sandwich, of questionable origin, that found in the fridge.

I'm used to working with huge, expensive statistical studies
at the interface of demographics and motivational psychology,
to be used in making decisions that will cost (or lose) millions,
sometimes billions -- I used to dramatize the risk of carelessness
for my people as the number of jobs lost. From a strictly
mathematical, theoretical statistical viewpoint, the number of
assumptions and guesstimates from experience one is required
to make even in a well-studied field can be disturbing, even
discouraging to the newbie until he discovers that applied
statistics is an art form for high rollers and the super-confident.


85.46% of all statistics are made up for the benefit of the current
audience. I'm fortunate in never having had to make a major financial
decision solely on the basis of statistics.

It's this background that leads me to welcome a meaningful,
simplifying, summing shortcut like your square-meter equivalent
circle. Together with the distance at which the light from
the lamp fills the circle and simple, well-known science,
in this case the inverse square root law,


That's called the "inverse square law". No "root" included. Lux
(brightness) is proportional to the square root of the change in
distance. Lumens (luminous flux) does not vary with distance.

it can let you estimate both the spread and the intensity
of a properly designed lamp at
distances useful to a bicyclist. Pity it won't tell you about
the hotspots as well, or nearfield spill from the thickness
of the lens, but then you can't have everything.


Opinions vary:
- Frank wants brightness limited to avoid blinding oncoming motorists.
- SMS wants some upwards spill to help see overhanging branches.
- You seem to want (not sure) more beamwidth to help see the roadside.
- NASA wants even lighting and no hot spot so that press release
photos look good.
- Barry wants only the forward facing area to be considered (beam
lumens), discarding the dim spillage as useless light.
- I want megalumens so I can set fire to the riders clothes ahead of
me. I also want megalumens because my principle use is "be seen"
lighting, which means I want to get the attention of motorists.

One number is definitely not going to be enough for a buy decision
from the above picky customers. The way I look at the problem is that
it's my light and I'll do with it what I find useful. If I want any
of the aforementioned illuminating aberrations, I'll do it somehow. If
conditions or ambient lighting changes, I want the ability to adjust
the intensity and beam pattern for those conditions. One number is
not going to work even for my buy (or make) decision.

So, why bother with lumens? Because in my never humble opinion, it's
a big part of the buy (or make) decision. I would guess(tm) it would
be #2, after beam pattern. It's not the sole criteria, it's not the
ultimate decision maker, and small differences are not going to
matter. Lumens are just one factor in the buy (or make) decision
which is currently horribly distorted by many vendors, and is not
easily verified by the buying public. What I'm trying to do is
provide the GUM (great unwashed masses) a means of verifying that the
stated lumens are something close to manufacturers claims. I believe
I've done that successfully.

Yo, Scharfie: I liked the integrating sphere until I discovered
you need a guy in a white coat to operate it. I'm allergic to men
in white coats: simply too much experience of ticket-punched
railroad minds telling me what I can't do, and expecting to be
paid after I did it myself. Men in white coats are never worth
the rise in blood pressure that accompanies their advent.


I have a white lab coat somewhere. I don't wear it any more because
I've grown in girth and it no longer fits. One of my competitors has
everyone wearing lab coats. To the customers, it creates the
impression that they know what they're doing.

I had one of my flashlights calibrated at the local university last
year. They wouldn't let me run the measurement, so I arranged (i.e.
bribed) a grad student to do the work. (He didn't wear a lab coat).
After about 45 mins of "calibration", he successfully produced a
number that was off by a factor of 10. We dug through the
measurements and calculations for about 10 mins and found the
arithmetic error. Incidentally, the professor in charge kept sticking
his head through the door and into the lab every 10 mins to check what
we were doing. He wore a white lab coat.

Andre Jute
Women in white coats are an altogether different matter


Nope. That usually represents a hospital or medical office
environment, which I do my best to avoid.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #29  
Old February 25th 18, 06:39 AM posted to rec.bicycles.tech
Frank Krygowski[_2_]
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Posts: 7,511
Default Inexpensive LUX meter from China to measure your bike lamp's output

On Saturday, February 24, 2018 at 10:10:41 PM UTC-5, Jeff Liebermann wrote:

Opinions vary:
- Frank wants brightness limited to avoid blinding oncoming motorists.


Well, that's an oversimplification at best. I don't want to blind anyone,
and I don't want other cyclists blinding me, which has happened many times.
But that calls for lower intensity only above the horizon. Lumens on the road
shouldn't cause that problem. Assuming, that is, they are properly spread. I
think "hot spots" tend to stop down one's pupils and decrease night vision.

Mostly, I object to the claims that something over 200 lumens is necessary.
I've done too much pleasant riding with B&M lights putting out less than 150
properly focused lumens. I think the cries for more are, at best, ill-informed.

However, it recently occurred to me that at this time of year, there might be
some utility to mega-lumen lights. If they were bright enough to melt the snow,
or (on a night like this) to dry the puddled roads ahead of the cyclist,
I might be convinced to use one. We're almost there.

- Frank Krygowski
  #30  
Old February 25th 18, 11:32 AM posted to rec.bicycles.tech
Sepp Ruf
external usenet poster
 
Posts: 454
Default Inexpensive LUX meter from China to measure your bike lamp'soutput

Frank Krygowski wrote:
On February 24, 2018 at 10:10:41 PM UTC-5, Jeff Liebermann wrote:

Opinions vary:
- Frank wants brightness limited to avoid blinding oncoming motorists.


Well, that's an oversimplification at best. I don't want to blind anyone,
and I don't want other cyclists blinding me, which has happened many times.
But that calls for lower intensity only above the horizon. Lumens on the road
shouldn't cause that problem. Assuming, that is, they are properly spread. I
think "hot spots" tend to stop down one's pupils and decrease night vision.

Mostly, I object to the claims that something over 200 lumens is necessary.
I've done too much pleasant riding with B&M lights putting out less than 150
properly focused lumens. I think the cries for more are, at best, ill-informed.

However, it recently occurred to me that at this time of year, there might be
some utility to mega-lumen lights. If they were bright enough to melt the snow,
or (on a night like this) to dry the puddled roads ahead of the cyclist,
I might be convinced to use one. We're almost there.


If the current crop of kickstarted U.S. bicycle lighting guys weren't
muscle-car tuners unsafely operating flasherless bicycles inside Kentucky
caves, with their trail beams set quite low, I'd recommend you try swapping
your non-selling Oculoss for a review sample of Outbound Lighting's Focal
Series Road Edition light:
https://www.outboundlighting.com/product/focal-series-road-edition


--
bicycle lighting, Italian rules, Team KATUSHA-Alpecin style:
https://www.youtube.com/embed/se-NIqzHaxw
(Italian audio is NSFW)
 




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