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  #271  
Old February 16th 20, 01:28 AM posted to rec.bicycles.tech
SMS
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Posts: 8,843
Default Better Braking?

On 2/15/2020 3:03 PM, wrote:

snip

I was replying to your pedantic remark 'As always: Sorry for introducing real numbers into a discussion. '. Those are not real numbers and certainly can not be checked. We have to believe you. In that case we can also believe Tom saying that thy dyno slowed him down considerably. BTW I think going from 20 to 19 mph is quite a bit for some. Bottom line is a dyno(hub) cost you 5-10 W, a battery powered light not.


It's very important to distinguish actual data from trusted sources from
data from untrusted sources which is also fabricated in order to attempt
to support a specific agenda.

Sadly, we've seen fabricated data for decades from the person you are
referring to. Fabricated data is worse than no data at all.
Ads
  #272  
Old February 16th 20, 04:33 AM posted to rec.bicycles.tech
Radey Shouman
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Posts: 1,421
Default Better Braking?

Sir Ridesalot writes:

On Saturday, 15 February 2020 12:32:22 UTC-5, Ted Heise wrote:
On Sat, 15 Feb 2020 08:50:32 -0600,
AMuzi wrote:
On 2/14/2020 10:18 PM, Frank Krygowski wrote:


Well, someone could always very precisely measure some aspect
another guy cares nothing about and call it 'data'.

I don't think it's better to give no measurements, nothing but
a vague "mine is better" opinion, and say "data doesn't
matter."


Regarding the topic, braking, ditto. No one disputes that big
fluid discs have better peak braking power and heat dissipation
for sustained braking power. One might chart those factors
impressively in comparison to rim brakes. For the bike I ride
this time of year, a simple sidepull front with fixed gear is
perfectly adequate and I've never wanted for more braking
power[1] on that bike given the way I use it. I'm not Jay, nor
Joerg, who have different needs and taste.

[1] what that bike really needs is a heater!


My fixed gear is set up the same way; that is, just a simple front
rim brake.

Just coming out of single digit temps here; this heater idea has
some appeal. Perhaps an e-bike battery could be re-purposed?


--
Ted Heise West Lafayette, IN, USA


A can of Sterno or similar gel-alcohol fuel mounted on a gimble mount,
and shielded from the wind will work. I did it once for fun. I had an
inverted funnel over the windshield of the Sterno can and a flexible
metal hose attached to the funnel and then insulated where I had it go
under my jacket.

Cheers


Build a man a fire, and he'll be warm for a day. Set a man on fire, and
he'll be warm for the rest of his life.

Terry Pratchett
  #273  
Old February 16th 20, 07:55 AM posted to rec.bicycles.tech
[email protected]
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Posts: 714
Default Better Braking?

On Sunday, February 16, 2020 at 12:57:47 AM UTC+1, jbeattie wrote:
On Saturday, February 15, 2020 at 2:30:14 PM UTC-8, Frank Krygowski wrote:
On Saturday, February 15, 2020 at 2:49:36 PM UTC-5, wrote:
On Saturday, February 15, 2020 at 8:00:21 PM UTC+1, Frank Krygowski wrote:
On 2/15/2020 3:16 AM, wrote:
On Saturday, February 15, 2020 at 5:30:59 AM UTC+1, Frank Krygowski wrote:
On Friday, February 14, 2020 at 7:40:02 PM UTC-5, Tom Kunich wrote:
On Friday, February 14, 2020 at 11:23:24 AM UTC-8, Sir Ridesalot wrote:
On Friday, 14 February 2020 12:00:11 UTC-5, Frank Krygowski wrote:
On 2/13/2020 5:47 PM, Tom Kunich wrote:
On Thursday, February 13, 2020 at 2:36:58 PM UTC-8, John B. Slocomb wrote:

Own Data? You mean like your assertions that a cheap Chinese
flashlight is a perfect bicycle head light? ...

I have taken Steven's word at the effectiveness of "cheap Chinese flashlights as bicycle lights" and he was completely correct. Sorry if you seem to think that you know anything about anything but you have shown yourself to be a great deal heavier on opinion than knowledge of anything..

You say Mr. Scharf was completely correct when he touted cheap Chinese
flashlights as bike headlights. That was when he said dyno powered
headlights were terrible and foolish.

Problem is, Mr. Scharf is now using dyno powered headlights on his
bikes, and no longer seems to say cheap Chinese flashlights are perfect.

My first question is, was he completely correct back then? Or is he
completely correct now?

My second question regards specific details. My dyno powered LED
headlights illuminate the entire width of the lane, and simultaneously
illuminate stop signs up to a quarter mile away from me, all without
blinding oncoming riders.

The Chinese flashlight I tried could not do that, no matter how I
adjusted the tilt and the focus. It was a truly crappy headlight. What,
specifically, does yours do? What's its brand and model?



--
- Frank Krygowski

Some people use flashlights that have a narrow beam but good range. Those lights might be okay as a be seen light but they don't light up much of the road. Others use flashlights with adjustable focus that spread the beams to light of more of the road. the trouble is that when they do that they lose the range they need if riding in totally dark conditions with no city lights.

I really like my CygoLite Rover II light as it does light up the two lanes of the country roads around here and it does so no matter what speed I'm riding at. Also, I can move the battery and light unit from bike to bike easily. I do wish it had a bit more range. For that reason I was considering getting the Centauri or Trident. Dynamo lights simply don't meet my needs.

Cheers

I think that there was a GCN video of a rim driven dynamo light and it was pretty funny because it was just like I remembered it as a kid. As you pushed the pedal down you would get a light and as you were changing over to the opposite the bike would stop from the massive resistance of a 30 watt dynamo. If Frank really uses those things he must ride a bike with a triple and a 26 to 42 gear ratio.

Tom, you have a problem confusing fantasy with reality.

Let me describe a spontaneous, unplanned dynamo test I did once. I've
described it before, but you probably wouldn't remember.

I was on a solo bike tour, heading to Bloomington IN where my kid was
soon to finish college. ("Dad, you've been talking about riding your
bike here. This is your last chance.")

I was on a nice, empty, flat four lane highway heading due west, and
feeling good because I was cranking along nicely at 20 mph despite my
full camping load.

Then I hit a bump in the pavement. After that, I heard some new noise
from my bike, and to my dismay my speed dropped about a mile per hour.

I remember checking for dragging brakes by squeezing the levers and
looking at the brake arms. Nothing. I didn't stop, but I worried
about what damage I had done that was slowing my bike. Then I realized
the bump had caused my generator to click on. I clicked it off and my
speed returned.

So at the power output needed for 20 mph, putting on the generator
slowed me to maybe 19 mph. This was with a bottom bracket generator,
but I haven't seen any real difference with a bottle dyno as I set
them up. And note, this matches Chris Juden's numbers that John
alluded to. Let me know if you need a link.

As always: Sorry for introducing real numbers into a discussion.

- Frank Krygowski

Hmm, you saying that your speed dropped from 20-19 mph in uncontrolled conditions are real numbers?

Those were the numbers I experienced. A dead flat four lane road with no
traffic is a fairly simple test situation. And again, it was at least
roughly corroborated by tests I've done and others have done.

Do you have different numbers?


--
- Frank Krygowski

It is crappy research Frank, you should know that. Maybe a tad better than saying 'these brakes are better' after using them for a longer time. Your real speed could went from 19.6 mph to 18.6 mph or from 19.6 mph to 19..4 mph. Who knows. When I was in the market for a dyno hub I wanted the one with the highest efficiency and my choice was based on measurements in a laboratory with real instruments. It is not difficult in these conditions to measure accurately. After my choice I'm not the least interested in numbers anymore and just use the damn thing and not trying to convince/impress others with numbers that don't say anything. When I switch the light on and of a don't notice anything in feel and speed but I have to reach down to switch it on or off which changes the situation so this doesn't anything either, but I know that I go from 6-7 Watt to 0.5-1 Watt turning in on and off.
BTW my good friend who is a skilled and enthusiast brick layer agrees with me.


You're losing track of the conversation, Lou. My post was to counter
Tom Kunich's claim that the dynamo slowed the bike almost to a stop.
His is an exaggerated variation on a frequent complaint - that dynos
make no sense because they slow a rider down.

I related what some researchers call "a natural experiment" - that is,
a change made inadvertently, or for reasons not connected to the
present question. Natural experiments can still yield reasonably good
data. Yes, in this case it wasn't as precise as laboratory data -
but then, if I gave laboratory data, Tom or other more obnoxious
people would say "That can't be trusted."

Mine was a real world experience. Conditions were constant except for
the sudden engagement of the dyno. The main weakness is that I know
the before and after speeds only approximately. But I know that there
was very little reduction in speed, which was all I cared about.

That is what you confirmed from your own experience. Yet you argue
with me! How odd.


Not odd at all. I don't doubt the drag scrubbed off some speed, but even your story suggests confounding factors like tracking down a noise, looking around for dragging brakes, etc. It's hard to do all those things while maintaining speed.

-- Jay Beattie.


The big problem with this 'test' is maintaining the same power. The natural tendency is to increase power when the resistance increases. Everyone who has ridden with a power meter know that the power varies significant even when trying to keep it constant. Plus minus 10 Watt is about the accuracy when you try to keep it constant if the restistance varies. Like I said the speed difference is crappy data.

Lou, going for another ride in the wet.
  #274  
Old February 16th 20, 02:21 PM posted to rec.bicycles.tech
Ted Heise
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Posts: 60
Default Equipping for the cold (was: Better Braking?)

On Sat, 15 Feb 2020 14:02:32 -0800,
Mark J. wrote:
On 2/15/2020 1:23 PM, Ted Heise wrote:
On Sat, 15 Feb 2020 10:08:04 -0800 (PST),
Sir Ridesalot wrote:
On Saturday, 15 February 2020 12:32:22 UTC-5, Ted Heise wrote:
On Sat, 15 Feb 2020 08:50:32 -0600,
AMuzi wrote:


[1] what that bike really needs is a heater!


Just coming out of single digit temps here; this heater idea
has some appeal. Perhaps an e-bike battery could be
re-purposed?


A can of Sterno or similar gel-alcohol fuel mounted on a
gimble mount, and shielded from the wind will work. I did
it once for fun. I had an inverted funnel over the
windshield of the Sterno can and a flexible metal hose
attached to the funnel and then insulated where I had it go
under my jacket.


Interesting. But where I really need the heat is my fingers
and toes!


Stick-on "chemical" toe warmers really help. By "chemical" I
mean powered by rusting/oxidation of iron filings (really).
They make a massive difference, especially if Reynaud's
syndrome (or more likely, a very mild version of Reynaud's) is
suspected.


Not Raynaud syndrome in my case, but I was diagnosed with venous
insufficiency a number of years ago--so my lower limb circulaton
is not great. I've been aware of the products you mention, and
may just have to get myself over the activation energy barrier to
try some!

--
Ted Heise West Lafayette, IN, USA
  #275  
Old February 16th 20, 03:11 PM posted to rec.bicycles.tech
Bertrand[_3_]
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Posts: 15
Default Better Braking?

I was replying to your pedantic remark 'As always: Sorry for introducing real numbers into a discussion. '. Those are not real numbers and certainly can not be checked. We have to believe you. In that case we can also believe Tom saying that thy dyno slowed him down considerably. BTW I think going from 20 to 19 mph is quite a bit for some. Bottom line is a dyno(hub) cost you 5-10 W, a battery powered light not.


Putting some numbers into bikecalculator.com suggests that the difference
between 20 and 19 mph is about 26 watts (207 vs. 181), which is a lot.
  #276  
Old February 16th 20, 07:22 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 8,437
Default Better Braking?

On 2/16/2020 2:55 AM, wrote:
On Sunday, February 16, 2020 at 12:57:47 AM UTC+1, jbeattie wrote:
On Saturday, February 15, 2020 at 2:30:14 PM UTC-8, Frank Krygowski wrote:

Mine was a real world experience. Conditions were constant except for
the sudden engagement of the dyno. The main weakness is that I know
the before and after speeds only approximately. But I know that there
was very little reduction in speed, which was all I cared about.

That is what you confirmed from your own experience. Yet you argue
with me! How odd.


Not odd at all. I don't doubt the drag scrubbed off some speed, but even your story suggests confounding factors like tracking down a noise, looking around for dragging brakes, etc. It's hard to do all those things while maintaining speed.

-- Jay Beattie.


The big problem with this 'test' is maintaining the same power. The natural tendency is to increase power when the resistance increases. Everyone who has ridden with a power meter know that the power varies significant even when trying to keep it constant. Plus minus 10 Watt is about the accuracy when you try to keep it constant if the restistance varies. Like I said the speed difference is crappy data.


Speed difference is what the dyno complainers worry about. I described
the speed difference I experienced in the real world under what
certainly seemed like perfectly constant conditions. The speed decrease
was minor.

Yes, it wasn't a laboratory test. Maybe an undetected tailwind popped up
at precisely the same time. Maybe my worries pumped adrenaline into my
system. Maybe the barometric pressure dropped. Maybe I hit a pocket of
warm air. And maybe all those factors went precisely away when I
realized what happened and turned the dyno back off.

But it occurs to me, this practical speed reduction shouldn't be too
hard to test, at least in an approximate way. Everyone here who does use
dynos of any type could pick an appropriate downhill and coast down it a
few times, with dyno turned on or turned off. Report your results.

My main point remains: Contrary to what Tom said, the decrease in speed
was, for me, minor. If I were going to race, I would keep the dyno
switched off. YMMV.

--
- Frank Krygowski
  #278  
Old February 16th 20, 07:44 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 8,437
Default Better Braking?

On 2/16/2020 10:11 AM, Bertrand wrote:
I was replying to your pedantic remark 'As always: Sorry for
introducing real numbers into a discussion. '. Those are not real
numbers and certainly can not be checked. We have to believe you. In
that case we can also believe Tom saying that thy dyno slowed him down
considerably. BTW I think going from 20 to 19 mph is quite a bit for
some. Bottom line is a dyno(hub) cost you 5-10 W, a battery powered
light not.


Putting some numbers into bikecalculator.com suggests that the
difference between 20 and 19 mph is about 26 watts (207 vs. 181), which
is a lot.


Assuming those calculations are correct: Is that "a lot"? How do we judge?

If told "It's enough to slow you down from 20 mph to 19 mph," I think
most people who were not riding to race would say "Oh, that's not so bad."

It's certainly not as bad as Tom pretended to believe, which was my main
point.

--
- Frank Krygowski
  #279  
Old February 16th 20, 11:20 PM posted to rec.bicycles.tech
JBeattie
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Posts: 4,669
Default Better Braking?

On Sunday, February 16, 2020 at 11:44:29 AM UTC-8, Frank Krygowski wrote:
On 2/16/2020 10:11 AM, Bertrand wrote:
I was replying to your pedantic remark 'As always: Sorry for
introducing real numbers into a discussion. '. Those are not real
numbers and certainly can not be checked. We have to believe you. In
that case we can also believe Tom saying that thy dyno slowed him down
considerably. BTW I think going from 20 to 19 mph is quite a bit for
some. Bottom line is a dyno(hub) cost you 5-10 W, a battery powered
light not.


Putting some numbers into bikecalculator.com suggests that the
difference between 20 and 19 mph is about 26 watts (207 vs. 181), which
is a lot.


Assuming those calculations are correct: Is that "a lot"? How do we judge?

If told "It's enough to slow you down from 20 mph to 19 mph," I think
most people who were not riding to race would say "Oh, that's not so bad."


It's bad if your killing yourself to hold 20mph to stay on a wheel, which I was actually doing the other night on my way home. Next time I'll shut off my light to see if it gives me any extra speed. I have my battery light that I use as a pulsing light and can use that. More dyno science experiments.. Next I'm going to get a Van de graaff generator for my bike or maybe a flux capacitor.

-- Jay Beattie.




  #280  
Old February 17th 20, 12:24 AM posted to rec.bicycles.tech
JBeattie
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Posts: 4,669
Default Better Braking?

On Saturday, February 15, 2020 at 11:55:23 PM UTC-8, wrote:
On Sunday, February 16, 2020 at 12:57:47 AM UTC+1, jbeattie wrote:
On Saturday, February 15, 2020 at 2:30:14 PM UTC-8, Frank Krygowski wrote:
On Saturday, February 15, 2020 at 2:49:36 PM UTC-5, wrote:
On Saturday, February 15, 2020 at 8:00:21 PM UTC+1, Frank Krygowski wrote:
On 2/15/2020 3:16 AM, wrote:
On Saturday, February 15, 2020 at 5:30:59 AM UTC+1, Frank Krygowski wrote:
On Friday, February 14, 2020 at 7:40:02 PM UTC-5, Tom Kunich wrote:
On Friday, February 14, 2020 at 11:23:24 AM UTC-8, Sir Ridesalot wrote:
On Friday, 14 February 2020 12:00:11 UTC-5, Frank Krygowski wrote:
On 2/13/2020 5:47 PM, Tom Kunich wrote:
On Thursday, February 13, 2020 at 2:36:58 PM UTC-8, John B.. Slocomb wrote:

Own Data? You mean like your assertions that a cheap Chinese
flashlight is a perfect bicycle head light? ...

I have taken Steven's word at the effectiveness of "cheap Chinese flashlights as bicycle lights" and he was completely correct. Sorry if you seem to think that you know anything about anything but you have shown yourself to be a great deal heavier on opinion than knowledge of anything.

You say Mr. Scharf was completely correct when he touted cheap Chinese
flashlights as bike headlights. That was when he said dyno powered
headlights were terrible and foolish.

Problem is, Mr. Scharf is now using dyno powered headlights on his
bikes, and no longer seems to say cheap Chinese flashlights are perfect.

My first question is, was he completely correct back then? Or is he
completely correct now?

My second question regards specific details. My dyno powered LED
headlights illuminate the entire width of the lane, and simultaneously
illuminate stop signs up to a quarter mile away from me, all without
blinding oncoming riders.

The Chinese flashlight I tried could not do that, no matter how I
adjusted the tilt and the focus. It was a truly crappy headlight. What,
specifically, does yours do? What's its brand and model?



--
- Frank Krygowski

Some people use flashlights that have a narrow beam but good range. Those lights might be okay as a be seen light but they don't light up much of the road. Others use flashlights with adjustable focus that spread the beams to light of more of the road. the trouble is that when they do that they lose the range they need if riding in totally dark conditions with no city lights.

I really like my CygoLite Rover II light as it does light up the two lanes of the country roads around here and it does so no matter what speed I'm riding at. Also, I can move the battery and light unit from bike to bike easily. I do wish it had a bit more range. For that reason I was considering getting the Centauri or Trident. Dynamo lights simply don't meet my needs.

Cheers

I think that there was a GCN video of a rim driven dynamo light and it was pretty funny because it was just like I remembered it as a kid. As you pushed the pedal down you would get a light and as you were changing over to the opposite the bike would stop from the massive resistance of a 30 watt dynamo. If Frank really uses those things he must ride a bike with a triple and a 26 to 42 gear ratio.

Tom, you have a problem confusing fantasy with reality.

Let me describe a spontaneous, unplanned dynamo test I did once. I've
described it before, but you probably wouldn't remember.

I was on a solo bike tour, heading to Bloomington IN where my kid was
soon to finish college. ("Dad, you've been talking about riding your
bike here. This is your last chance.")

I was on a nice, empty, flat four lane highway heading due west, and
feeling good because I was cranking along nicely at 20 mph despite my
full camping load.

Then I hit a bump in the pavement. After that, I heard some new noise
from my bike, and to my dismay my speed dropped about a mile per hour.

I remember checking for dragging brakes by squeezing the levers and
looking at the brake arms. Nothing. I didn't stop, but I worried
about what damage I had done that was slowing my bike. Then I realized
the bump had caused my generator to click on. I clicked it off and my
speed returned.

So at the power output needed for 20 mph, putting on the generator
slowed me to maybe 19 mph. This was with a bottom bracket generator,
but I haven't seen any real difference with a bottle dyno as I set
them up. And note, this matches Chris Juden's numbers that John
alluded to. Let me know if you need a link.

As always: Sorry for introducing real numbers into a discussion.

 




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