Bicycle DRLs - Actually reading the paper, actually looking at the

On Sat, 18 Jul 2015 11:33:53 +0000 (UTC), Duane
wrote:

Lou Holtman wrote:
On 2015-07-18 10:45:27 +0000, Duane said:

Lou Holtman wrote:
On 2015-07-18 00:34:32 +0000, John B. Slocomb said:
On Fri, 17 Jul 2015 09:31:15 -0700, sms
wrote:
On 7/14/2015 5:06 PM, John B. Slocomb wrote:
snip
But just to be sure, are you competent to make such a statement
because you are a properly trained metal worker? You have some years
in the trade? If so could you please provide some evidence that this
is so.
You just confirmed what I said. Unless you are a properly trained metal
worker, you should not be drilling holes in your bicycle frame to put in
Rivnuts. Pretty sure most cyclists would agree with that assessment.
No, I was commenting on your ability to make an educated decision.
I think you're failing to distinguish between someone that is skilled in
metal working and a professional metal worker. I'm sure that there are
lay people out there that have a workshop at home with sufficient
equipment to be properly aligning, positioning, and drilling holes in
their frames (as long as they don't mind losing the frame's lifetime
warranty). But most cyclists don't fall into that category.
Actually I just installed some riv-nuts in an aluminum frame that I am
slowly rebuilding. The required tools were a white board marker, a
ruler, a hand drill (the sort you turn by hand) and a drill bit of
course, a nail and a rock.
Use the ruler, as a straight edge, and the marker to draw a straight
line on the frame, the ruler, as a measuring device, to mark the
distance between the holes, roughly a +- tolerance of 1/4", the nail
and rock to "center" punch the marks for drilling and the hand drill
to drill the holes.
This is rocket science and beyond the abilities of the modern
American?
I think the question is not whether you could install a rivnut, but
whether the integrity of the frame stays in tact after that. In this
regard SMS is a little paranoid.
Probably not wrong about the warranty being voided though.

True, but who is expecting warranty after drilling holes in a frame? That
would be very naive.

True. In my case I have 2 bikes. One is CF and won't be drilled at all.
The other is a 93 crop moly steel lugged bianchi that's too nice too be
drilled. So I have no interest either way.

One doesn't install "riv-nuts" in a steel frame. One uses "braze ons",
with tiny little diamond shaped reinforcing plates if one want to be
very up-market :-)
--
cheers,

John B.

On Sun, 19 Jul 2015 10:33:46 +1000, James
wrote:

On 18/07/15 22:10, John B. Slocomb wrote:
On Sat, 18 Jul 2015 07:45:09 +0200, Lou Holtman
wrote:

On 2015-07-18 00:34:32 +0000, John B. Slocomb said:

On Fri, 17 Jul 2015 09:31:15 -0700, sms
wrote:

On 7/14/2015 5:06 PM, John B. Slocomb wrote:

snip

But just to be sure, are you competent to make such a statement
because you are a properly trained metal worker? You have some years
in the trade? If so could you please provide some evidence that this
is so.

You just confirmed what I said. Unless you are a properly trained metal
worker, you should not be drilling holes in your bicycle frame to put in
Rivnuts. Pretty sure most cyclists would agree with that assessment.

No, I was commenting on your ability to make an educated decision.

I think you're failing to distinguish between someone that is skilled in
metal working and a professional metal worker. I'm sure that there are
lay people out there that have a workshop at home with sufficient
equipment to be properly aligning, positioning, and drilling holes in
their frames (as long as they don't mind losing the frame's lifetime
warranty). But most cyclists don't fall into that category.

Actually I just installed some riv-nuts in an aluminum frame that I am
slowly rebuilding. The required tools were a white board marker, a
ruler, a hand drill (the sort you turn by hand) and a drill bit of
course, a nail and a rock.

Use the ruler, as a straight edge, and the marker to draw a straight
line on the frame, the ruler, as a measuring device, to mark the
distance between the holes, roughly a +- tolerance of 1/4", the nail
and rock to "center" punch the marks for drilling and the hand drill
to drill the holes.

This is rocket science and beyond the abilities of the modern
American?

I think the question is not whether you could install a rivnut, but
whether the integrity of the frame stays in tact after that. In this
regard SMS is a little paranoid.

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

But not to extent that one has to get excited about it. Helicopter
main rotors are usually a thick aluminum leading edge on an aluminum
covered foam airfoil. I was called out one day to "Measure dents in
helicopter blade" and found that there are allowable dents and gashes
in the aluminum leading edge. They vary in allowable depth depending
on how far out from the hub they are but they can be surprisingly
deep.

I asked the crew chief how they happened and he said, "Oh, they hit a
tree". Apparently it is a fairly common event when flying around in
jungles :-)
--
cheers,

John B.

On Sun, 19 Jul 2015 16:51:17 +0100, Phil W Lee
wrote:

Frank Krygowski considered Sat, 18 Jul 2015
22:48:05 -0400 the perfect time to write:

On 7/18/2015 8:33 PM, James wrote:
On 18/07/15 22:10, John B. Slocomb wrote:

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

One of my friends (whom I see only occasionally) is certified as an
airframe & powerplant mechanic for airplanes, although he switched
careers and became a very impressive engineer.

Anyway, I not-quite-recall him saying something about techniques used to
prevent stress concentration problems when working on aluminum airplane
skin. Perhaps peening the metal afterwards? I forget.

It's probably about time for me to pay him a visit. But in the
meantime: Anyone know about that?

In stress bearing airframe fastenings, all that is necessary is to
ream and de-burr a drilled hole in aluminium to comply with all ADs
(Airworthiness Directives) I've ever even heard of, and I've WATCHED
an airframe designer teaching a mechanic to do exactly that when
building and installing a replacement for a major stress carrying
component during a restoration.

I've never even seen an "airframe designer" to say nothing of one
teaching me anything :-) And I have had a U.S. government license to
work on airplanes and engines for a long time now. And the twenty
years I spent in the U.S. Air Force was all in one phase or another of
the aircraft maintenance field. And, yes, the directive says to drill
the rivet hole, than deburr the rivet hole and than drive the rivet,
and for twenty something years I've watched "Tin-Benders" merrily
drill holes and drive rivets without deburring anything. And I've yet
to see a riveted joint fail.... except for a DC-3 that crashed on
take-off and that might have been hostile fire that caused that :-)


You can stand around watching restorations of some very interesting
aircraft at Duxford, just down the road from me.
If you wait until they are between tasks, they are usually quite
willing to answer questions, as well.

So even for the most paranoid, drilling slightly undersized then
reaming to the exact size and de-burring is all that is necessary,
even in aluminium. In steel, I'd go straight to the correct size (but
de-burr anyway, as a matter of general principle).

I can honestly say that I have never seen a 1/8" reamer in any
sheetmetal workers tool box. But they usually have a dozen or more
1/8" drills.

About the only manufacturer advantage I can think of (and one
strangely not mentioned by Scharfe) is that the frame manufacturer may
have some detailed knowledge of places where a particular design of
frame has a known weak spot or hidden stress riser, where installing
anything may be a bad idea (right on the step of a butted tube, for
example).

But the tube butts are there to reinforce the tube because the joint
is being made and 1 mm tube is damned hard to weld or braze
consistently in a manufacturing environment.
--
cheers,

John B.

On Sun, 19 Jul 2015 17:08:08 +0100, Phil W Lee
wrote:

John B. Slocomb considered Sun, 19 Jul 2015
14:09:57 +0700 the perfect time to write:

On Sun, 19 Jul 2015 10:33:46 +1000, James
wrote:

On 18/07/15 22:10, John B. Slocomb wrote:
On Sat, 18 Jul 2015 07:45:09 +0200, Lou Holtman
wrote:

On 2015-07-18 00:34:32 +0000, John B. Slocomb said:

On Fri, 17 Jul 2015 09:31:15 -0700, sms
wrote:

On 7/14/2015 5:06 PM, John B. Slocomb wrote:

snip

But just to be sure, are you competent to make such a statement
because you are a properly trained metal worker? You have some years
in the trade? If so could you please provide some evidence that this
is so.

You just confirmed what I said. Unless you are a properly trained metal
worker, you should not be drilling holes in your bicycle frame to put in
Rivnuts. Pretty sure most cyclists would agree with that assessment.

No, I was commenting on your ability to make an educated decision.

I think you're failing to distinguish between someone that is skilled in
metal working and a professional metal worker. I'm sure that there are
lay people out there that have a workshop at home with sufficient
equipment to be properly aligning, positioning, and drilling holes in
their frames (as long as they don't mind losing the frame's lifetime
warranty). But most cyclists don't fall into that category.

Actually I just installed some riv-nuts in an aluminum frame that I am
slowly rebuilding. The required tools were a white board marker, a
ruler, a hand drill (the sort you turn by hand) and a drill bit of
course, a nail and a rock.

Use the ruler, as a straight edge, and the marker to draw a straight
line on the frame, the ruler, as a measuring device, to mark the
distance between the holes, roughly a +- tolerance of 1/4", the nail
and rock to "center" punch the marks for drilling and the hand drill
to drill the holes.

This is rocket science and beyond the abilities of the modern
American?

I think the question is not whether you could install a rivnut, but
whether the integrity of the frame stays in tact after that. In this
regard SMS is a little paranoid.

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

But not to extent that one has to get excited about it. Helicopter
main rotors are usually a thick aluminum leading edge on an aluminum
covered foam airfoil. I was called out one day to "Measure dents in
helicopter blade" and found that there are allowable dents and gashes
in the aluminum leading edge. They vary in allowable depth depending
on how far out from the hub they are but they can be surprisingly
deep.

I asked the crew chief how they happened and he said, "Oh, they hit a
tree". Apparently it is a fairly common event when flying around in
jungles :-)

Notching of (aluminium) propellers on fixed wing aircraft is not
uncommon either (particularly when operating from un-paved or badly
maintained runways), and needs to be pretty extreme to be a problem.
I've called the resident certified A&P to dress a few bad ones out,
which was done with an ordinary file, no polishing necessary.
Apparently, if it's bad enough that dressing it out creates a serious
imbalance, THAT is the concern, well ahead of any weakening.

In thinking back I don't remember ever seeing any concern about
propellers and when I was first in Japan the B-29's operated from PSP
taxi ways so there likely some prop damage due to rocks and gravel. In
fact I can't remember but once seeing a propeller changed (other than
due to an engine change) and that was because the pitch changing
mechanism was malfunctioning.
--
cheers,

John B.

On Monday, July 13, 2015 at 8:53:57 AM UTC-7, Frank Krygowski wrote:
Another thread mentions Madsen et. al., "Safety Effects of Permanent
Running Lights for Bicycles", Accident Analysis & Prevention 50 (2013)
820-829. Scharf said "Read the study," But I'm pretty sure he's read
only the abstract. I downloaded the study and skimmed it a few days
ago. Last night I took the time to read it in detail. Here's what I found.

One might say the study is a promotion of the Reelight flashing light
system, powered by magnets on wheel spokes.
https://www.reelight.com/en/ Those are the lights "tested" in the
study. And there are enough weirdnesses in the results to indicate that
this is more a promotion than a serious study. Here are details and
(warning!) data analysis.

They advertized they wanted to do a study and asked who in Odense wanted
to participate in a light study, luring participants by promising free
lights. They got over 18000 applicants, about 10% of the population.
That's the first "self-selection" clue. Those who already had
sufficient lighting, those who didn't care about lights and those who
simply didn't hear about this would be excluded.

They used a random process to select 1845 of those people to get lights
immediately and 2000 people to act as a control group, promising the
controls free lights if they stayed in the study for a full year.
Obviously, those who got the lights knew they had them, so there's
nothing "blind" about this study. Placebo effects are certainly
possible, and certainly did occur - see below. Some people dropped out
in the course of the 1-year time period. 3306 completed the entire year.

The study scheme echoed one "Danger! Danger!" study from Portland, in
that they emailed the paricipants every two months (Portland used one
month) to ask about any bike "accidents" and "injuries." This is so
participants wouldn't forget any of those. It seems to me that if an
"accident" or "injury" is forgettable, it should be below the radar, so
to speak. But they didn't want to miss even the most minor "incident."

They defined "accident" as "an incident where you are forced off your
bike and/or crashed either by yourself or due to collision OR
NEAR-COLLISION with others." So actually, a near miss counted as an
"accident"! And I suppose "forced off you bike" could be coming to a
stop and having the bike topple as you stand over it. IOW, they are
exaggerating dangers, as usual. More on that later.

The paper does not define "injury," but recall that the Portland paper
counted _any_ injury. I assume this one did too. Broken fingernail?
Injury! But the injuries were still extremely rare.

Overall, there were 39672 "man-months" of bike use recorded. There was
no data on number of trips by bike, km traveled or hours exposure;
therefore all "rates" are "per man-month." And the numbers are very low
indeed.

Exactly how low is a bit difficult to tell. Examining data from three
of the paper's tables and doing some minor number crunching gave three
different answers for injuries per man-month. Table 6 works out to
0.00103 injuries per man-month; table 8 claims 0.00489 instead; and
table 9 implies 0.00318 instead. There may be something I'm missing;
but whichever is correct, all those figures are extremely low! The
worst yields an average of 204 months or 17 years of riding per
"injury," including (I assume) very minor and forgettable injuries.
Only 41 injuries were seen by medical people, and apparently none were
serious. Does that sound dangerous?

Similarly, accident rates per man-month were very low - only 261
"accidents" (including near-misses!) from 39672 man-months exposure.
That's less than 0.007 "accidents" per man-month, including (I assume)
putting one's foot down if one drops his bike.

Regarding the type of "accident": It would certainly be good to collect
data on what specific type of "accident" occurred or were "prevented."
But there's absolutely no mention of that in the paper. They give
separate numbers for winter vs. summer, daylight vs. darkness, solo vs.
"multiparty," etc. but nothing at all about whether they were cars
pulling out, left crosses, right hooks, cyclists running stop signs,
pedestrians jumping out, bike-bike collisions or anything else. This
makes actual analysis of causes impossible.

However, since "solo" accidents are listed, those must be simple falls
due to skidding, running into objects or pavement defects, simply losing
one's balance, etc. REELIGHTS SUPPOSEDLY PREVENTED ABOUT 25% OF SOLO
CRASHES! The authors acknowledge that this is flat impossible, and
evidence that the riders with the lights are cooking their reports, i.e.
not reporting some accidents.

The authors attempt a crude correction for this effect, but I see no
justification for its accuracy - certainly not down to the three
significant figure reporting of results. Still, they tried using their
correction (i.e. fudge factor) to improve their results, and (bottom of
page 827) said "... a result of the applied correction... has the effect
that NONE OF THE ESTIMATED DIFFERENCES IN THE INCIDENCE RATES ARE
[STATISTICALLY] SIGNIFICANT, the incidence rates for multiparty
accidents being the only but very important exception."

OK, so what's the rate of those multiparty (bike-ped, bike-bike,
bike-car) "accidents" (including near misses, which are not really
accidents? It's 0.00178 "accidents" per man-month. That means an
average of 562 months or 47 years of riding between each of those
"accidents" (including near misses).

How does this relate to Scharf's and Joerg's claims that DRLs make a
huge, obvious difference? As usual, the actual numbers indicate a very
strong probability of bull****. And the bull**** applies to the paper's
conclusions regarding Reelights' magic effectiveness as well.

This paper, like so many others, emphasizes changes in extremely rare
hazards. Even if Reelights or other DRLs reduce "accidents" (including
near misses) from - say - once every 47 years to once every 88 years on
average, which is what they claim - is it really worth yelling "Danger!
Danger! Buy our lights!"

Well, I suppose if you own the Reelight company, or if you get a
commission by selling Chinese flashlights on your web pages, you'll say
it's worth it. Less biased people probably have other opinions. Which
is why, contrary to Scharf's statements, only a minuscule percentage of
cyclists use daytime running lights.

I rode in this morning behind a guy with a rear-facing white-light flasher -- a small job that put out a ton of light. It was truly amazing. I wanted to ask the guy who made it, but I was having too much trouble stifling my desire to smack him upside the head. It was hanging off his backpack at eye level, blasting my retinas. What a dork. I'm sure, though, that he was really, really safe. It wasn't safe for me because I had to find a gap in traffic to jump around the moron.

There were some other people in the conga line this morning with dim little throbbing flashers that I would notice AFTER I saw the rider -- the safety light version of a lucky rabbit's foot. It must have been "ride to work day" because there was a higher than average number of bad riders -- and there was a direct correlation between the bad-ness of the rider and the amount of safety paraphernalia. These riders would be vastly safer if they just didn't ride like squirrels. Dressing a squirrel in an orange vests does not make it safe. http://img0.etsystatic.com/000/0/661...294079626..jpg

-- Jay Beattie.

On 7/20/2015 8:41 PM, jbeattie wrote:
Dressing a squirrel in an orange vests does not make it safe.
http://img0.etsystatic.com/000/0/661....294079626.jpg

But that squirrel isn't flat. Isn't that proof that his orange vest
saved his life??

--
- Frank Krygowski

On Tuesday, July 21, 2015 at 1:42:01 AM UTC+1, jbeattie wrote:
http://img0.etsystatic.com/000/0/661....294079626.jpg

-- Jay Beattie.

Federal Squirrel. In November 2016, will y'all be electing him President?

Andre Jute
Just asking

On Tuesday, July 21, 2015 at 4:14:16 AM UTC-7, Andre Jute wrote:
On Tuesday, July 21, 2015 at 1:42:01 AM UTC+1, jbeattie wrote:
http://img0.etsystatic.com/000/0/661....294079626.jpg

-- Jay Beattie.

Federal Squirrel. In November 2016, will y'all be electing him President?

Aren't you running for the Republican nomination? Most people are.

-- Jay Beattie.

On Tuesday, July 21, 2015 at 3:31:01 PM UTC+1, jbeattie wrote:
On Tuesday, July 21, 2015 at 4:14:16 AM UTC-7, Andre Jute wrote:
On Tuesday, July 21, 2015 at 1:42:01 AM UTC+1, jbeattie wrote:
http://img0.etsystatic.com/000/0/661....294079626.jpg

-- Jay Beattie.

Federal Squirrel. In November 2016, will y'all be electing him President?

Aren't you running for the Republican nomination? Most people are.

-- Jay Beattie.

Thanks for the offer, but I must decline as I'm not 35 yet.

Andre Jute
But then most Presidents aren't either...

On Tue, 21 Jul 2015 15:42:51 +0100, Phil W Lee
wrote:

John B. Slocomb considered Mon, 20 Jul 2015
08:40:08 +0700 the perfect time to write:

On Sun, 19 Jul 2015 17:08:08 +0100, Phil W Lee
wrote:

John B. Slocomb considered Sun, 19 Jul 2015
14:09:57 +0700 the perfect time to write:

On Sun, 19 Jul 2015 10:33:46 +1000, James
wrote:

On 18/07/15 22:10, John B. Slocomb wrote:
On Sat, 18 Jul 2015 07:45:09 +0200, Lou Holtman
wrote:

On 2015-07-18 00:34:32 +0000, John B. Slocomb said:

On Fri, 17 Jul 2015 09:31:15 -0700, sms
wrote:

On 7/14/2015 5:06 PM, John B. Slocomb wrote:

snip

But just to be sure, are you competent to make such a statement
because you are a properly trained metal worker? You have some years
in the trade? If so could you please provide some evidence that this
is so.

You just confirmed what I said. Unless you are a properly trained metal
worker, you should not be drilling holes in your bicycle frame to put in
Rivnuts. Pretty sure most cyclists would agree with that assessment.

No, I was commenting on your ability to make an educated decision.

I think you're failing to distinguish between someone that is skilled in
metal working and a professional metal worker. I'm sure that there are
lay people out there that have a workshop at home with sufficient
equipment to be properly aligning, positioning, and drilling holes in
their frames (as long as they don't mind losing the frame's lifetime
warranty). But most cyclists don't fall into that category.

Actually I just installed some riv-nuts in an aluminum frame that I am
slowly rebuilding. The required tools were a white board marker, a
ruler, a hand drill (the sort you turn by hand) and a drill bit of
course, a nail and a rock.

Use the ruler, as a straight edge, and the marker to draw a straight
line on the frame, the ruler, as a measuring device, to mark the
distance between the holes, roughly a +- tolerance of 1/4", the nail
and rock to "center" punch the marks for drilling and the hand drill
to drill the holes.

This is rocket science and beyond the abilities of the modern
American?

I think the question is not whether you could install a rivnut, but
whether the integrity of the frame stays in tact after that. In this
regard SMS is a little paranoid.

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

But not to extent that one has to get excited about it. Helicopter
main rotors are usually a thick aluminum leading edge on an aluminum
covered foam airfoil. I was called out one day to "Measure dents in
helicopter blade" and found that there are allowable dents and gashes
in the aluminum leading edge. They vary in allowable depth depending
on how far out from the hub they are but they can be surprisingly
deep.

I asked the crew chief how they happened and he said, "Oh, they hit a
tree". Apparently it is a fairly common event when flying around in
jungles :-)

Notching of (aluminium) propellers on fixed wing aircraft is not
uncommon either (particularly when operating from un-paved or badly
maintained runways), and needs to be pretty extreme to be a problem.
I've called the resident certified A&P to dress a few bad ones out,
which was done with an ordinary file, no polishing necessary.
Apparently, if it's bad enough that dressing it out creates a serious
imbalance, THAT is the concern, well ahead of any weakening.

In thinking back I don't remember ever seeing any concern about
propellers and when I was first in Japan the B-29's operated from PSP
taxi ways so there likely some prop damage due to rocks and gravel. In
fact I can't remember but once seeing a propeller changed (other than
due to an engine change) and that was because the pitch changing
mechanism was malfunctioning.

Light aircraft like the ones I was flying usually have much lower
clearance between the prop and the ground.
And many (most?) small airfields in the UK (typical bases for flying
schools) are ex-WW2 bases that have seen little maintenance since.
The one I trained at was unusual as it actually did have an ex-council
road sweeping machine which swept the runways two or three times a
year. Taxiways weren't as well maintained, but then you don't
generally use enough power on them to throw gravel around. But
depending on wind direction, there's always someone who does his power
checks on a taxiway. And of course, a high proportion of users are
student pilots, which has it's own hazards.

I assume that there must be some damage, sometimes, as I faintly
remember years ago being told how to repair wooden propellers. They
had a metal covering over the leading edge and apparently got dented
occasionally. I remember that you filled in the dents with solder and
than filed them smooth and of course then had to rebalance the
propeller :-)

--
cheers,

John B.