#291
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Better Braking?
On 2/16/2020 10:26 PM, jbeattie wrote:
On Sunday, February 16, 2020 at 6:59:54 PM UTC-8, Frank Krygowski wrote: On 2/16/2020 6:20 PM, jbeattie wrote: 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. Wow. What prize was in contention? None. I was getting towed by a friend and didn't want to lose a wheel. Is this a foreign concept? No, except I've almost always been the guy in front, checking frequently to see that the person behind is doing OK. I slow a bit if they're struggling. Admittedly, I'm getting old, so I'll be experiencing more of your problem, I'm sure. Our very first century ride (almost 45 years ago!) was my wife and I with another newbie friend. He was as strong as I was, so stronger than my wife. He and I took turns pulling with my wife riding third. I had to explain to him that in that situation, his objective on a hill or rise should not be to keep a constant speed. It's better to shoot for a constant power output. Otherwise the person you're trying to help will fall off and have to struggle to catch back up. That ride started far from our home, and we were late arrivals. When we got to the lunch stop, the hosting club members said "Sorry, we ran out of food." And like true novices, in our excitement we had left our wallets in my car. That was my first and probably worst experience with The Bonk. Our pasta dinner afterwards seemed heavenly. -- - Frank Krygowski |
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#292
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Better Braking?
On Sunday, February 16, 2020 at 11:20:53 PM UTC, jbeattie wrote:
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. Not to nitpick like some much-disputed party here, but while you're about it, get a trailer so you can tow your own nuclear power generator. By the Krygowski-Disputed Measurement, you're sure to go faster that with your own nuclear power. Andre Jute Conservationist |
#293
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Better Braking?
On Monday, February 17, 2020 at 9:14:17 AM UTC-8, Frank Krygowski wrote:
On 2/16/2020 10:26 PM, jbeattie wrote: On Sunday, February 16, 2020 at 6:59:54 PM UTC-8, Frank Krygowski wrote: On 2/16/2020 6:20 PM, jbeattie wrote: 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. Wow. What prize was in contention? None. I was getting towed by a friend and didn't want to lose a wheel. Is this a foreign concept? No, except I've almost always been the guy in front, checking frequently to see that the person behind is doing OK. I slow a bit if they're struggling. Admittedly, I'm getting old, so I'll be experiencing more of your problem, I'm sure. You'd be in the rear view mirror with this guy. The dynamic on this part of the commute is an uninterrupted 2 mile TT segment with a 2% grade. And "friend" is probably too strong of a word; the guy was just someone I know from the racks who was giving me a tow. If I had totally blown, he might have slowed, but I wasn't going to find out -- and I also did the "I'm going this way" subterfuge and took a modified route through the hills, on what legs I had left. Riding up the eastside with my son the human eBike, we'd get a paceline, and riders would drop in and get shelled out. Some mornings were like a little Cat 5 criterium -- which is not a good thing if you have a sketchy pack on a MUP. This segment is a piece of the eastside commute: https://bikeportland.org/2017/12/19/...the-u-s-261628 So, along with the commuter pack, you end up with people trying to set a record on that segment, which means holding 30mph, which didn't seem that difficult for my son, and for me it was like drafting a car. -- Jay Beattie. |
#294
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Better Braking?
On 2/17/2020 1:32 PM, jbeattie wrote:
On Monday, February 17, 2020 at 9:14:17 AM UTC-8, Frank Krygowski wrote: On 2/16/2020 10:26 PM, jbeattie wrote: On Sunday, February 16, 2020 at 6:59:54 PM UTC-8, Frank Krygowski wrote: On 2/16/2020 6:20 PM, jbeattie wrote: 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. Wow. What prize was in contention? None. I was getting towed by a friend and didn't want to lose a wheel. Is this a foreign concept? No, except I've almost always been the guy in front, checking frequently to see that the person behind is doing OK. I slow a bit if they're struggling. Admittedly, I'm getting old, so I'll be experiencing more of your problem, I'm sure. You'd be in the rear view mirror with this guy. No doubt. There are more guys like that every year. And sadly, it's not really because the guys are getting faster. :-/ -- - Frank Krygowski |
#295
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Better Braking?
On Mon, 17 Feb 2020 06:29:14 -0800 (PST), Tom Kunich
wrote: On Saturday, February 15, 2020 at 12:16:36 AM UTC-8, 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? Lou If you have an upright posture touring bike it takes about 180 watts to go 20 mph and 160 watts to go 19 mph. Those headlights are 10 watts at the very least and they lose about three times that power to get that much light since they are filament bulbs. Framk just told us that 1. He ever in his life could ride a steady 20 mph. 2. That he had a sidewall generators that he could not detect was on (they make a hell of a racket) and 3. That he only lost one mph when it was engaged - 20 watts. I'm having a laughing fit at the moment. 20 watts? Oh you mean like the "Lowrider Dynamo Generator 12V sidewall generator"? That is actually a 6 watt generator? https://www.amazon.com/Lowrider-Gene...1982134&sr=8-3 Or maybe the "Bicycle Motorized Dynamo Generator 6V"? That is actually 3 watts? https://www.amazon.com/Motorized-Gen... 134&sr=8-22\ Or is the 20 watts just your over heated imagination working overtime? -- cheers, John B. |
#296
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Better Braking?
On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich
wrote: On Saturday, February 15, 2020 at 6:50:46 AM UTC-8, AMuzi wrote: On 2/14/2020 10:18 PM, Frank Krygowski wrote: On Friday, February 14, 2020 at 6:34:47 PM UTC-5, AMuzi wrote: On 2/14/2020 5:05 PM, Frank Krygowski wrote: On 2/14/2020 5:47 PM, John B. wrote: On Fri, 14 Feb 2020 21:35:18 -0000 (UTC), Duane wrote: jbeattie wrote: On Friday, February 14, 2020 at 11:35:46 AM UTC-8, Duane wrote: On 2/14/2020 2:23 PM, 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 imagine it depends on what you want. I use a Planet Bike 2w when I'm doing club rides in the evening because it's dark on my ride back home from the start. But I'm not out in the country, only the burbs. I don't need a lot of distance but I need something to show me the potholes in enough time to avoid them. My guess is that a flashlight would probably work in that case. Then you have people riding in the rain, pitch dark, pitch dark rain down steep declines etc. etc. etc. I seriously doubt that there's a one for all solution. In the latter circumstances, a dyno clearly is not the solution. In stormy weather, fast downhill or trail, a bright battery light is best . . . for me, and speaking as someone who owns a dyno and battery lights. I can A/B my dyno and my little all-in-on L&M Urban 800 every night since I use both. The L&M produces far better light; it is one fourth the total price of my dyno set up and suffers only in that it requires charging. -- Jay Beattie. Like I’ve said before most of times that I’m riding at night it’s by accident. The few planned times are as I described. So a dyno doesn’t do much for me. Oddly, "riding at night by accident" is one of the main reasons I settled on dyno lights. A big event for me was being on a solo tour in Middle-Of-Nowhere Township, trying to get to a particular state park. It was hillier than I anticipated, dinner in a restaurant took extra long, and surprise, I had to do the last few miles in the dark. So I pulled out the battery light I'd brought and turned it on. The batteries got me to, oh, 3 to 5 miles from the campground. Then nothing. On a two lane country highway. Fortunately, traffic was light. I finished by pulling way off the side of the road whenever a car came. I then installed a dyno on every bike. Since then, there have been countless times I didn't plan on riding in the dark, but had to - meetings that ran long, extra work to get done, having too much fun to leave, etc. It's no problem. My lights are just like those on my car. No preparation needed, just turn them on and they work. I can see that wouldn't be valuable for people who use their bikes differently than I do. As for charging, it’s pretty much routine. I have to charge my phone, my Garmin, my lights and even my watch. Pfft. Battery charge is now an issue. A Garmin and a phone that can last for a 175km ride hS become a thing. Again, we all have different requirements. The fact that we all ride bikes is way cool. Too bad we can’t avoid the bull**** here. and then a thread would look like: Hey! I use a Gamnin! ----- You do? So do I. ---- Wow! I use one too. --- Doesn't everybody use a Garmin? --- So cheap they ought to. --- :-) :-) And it would require so little technical thinking! Win - win! 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." What do you use for lights? How well do they work for you? Why? - Frank Krygowski Exactly. You and I have chosen no-switch always-on dynamos with which we are satisfied based on convenience and dependability with virtually zero maintenance. Heated discussions of amp hours, megalumens and optic patterns may be vaguely interesting but not relevant to my (our?) cycling. 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! -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. AND ONCE AGAIN THE INDOMONIBLE TOMMIE PROVES TO THE WORLD that he doesn't know what he is talking about. When Frank is telling us that he only lost on mph at a speed where he is generating almost his entire output capacity my eyes are rolling and so must everyone's. No Tommy, the eyes are rolling because you don't know what you are talking about. -- cheers, John B. |
#297
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Better Braking?
John B. wrote:
On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich wrote: On Saturday, February 15, 2020 at 6:50:46 AM UTC-8, AMuzi wrote: On 2/14/2020 10:18 PM, Frank Krygowski wrote: On Friday, February 14, 2020 at 6:34:47 PM UTC-5, AMuzi wrote: On 2/14/2020 5:05 PM, Frank Krygowski wrote: On 2/14/2020 5:47 PM, John B. wrote: On Fri, 14 Feb 2020 21:35:18 -0000 (UTC), Duane wrote: jbeattie wrote: On Friday, February 14, 2020 at 11:35:46 AM UTC-8, Duane wrote: On 2/14/2020 2:23 PM, 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 imagine it depends on what you want. I use a Planet Bike 2w when I'm doing club rides in the evening because it's dark on my ride back home from the start. But I'm not out in the country, only the burbs. I don't need a lot of distance but I need something to show me the potholes in enough time to avoid them. My guess is that a flashlight would probably work in that case. Then you have people riding in the rain, pitch dark, pitch dark rain down steep declines etc. etc. etc. I seriously doubt that there's a one for all solution. In the latter circumstances, a dyno clearly is not the solution. In stormy weather, fast downhill or trail, a bright battery light is best . . . for me, and speaking as someone who owns a dyno and battery lights. I can A/B my dyno and my little all-in-on L&M Urban 800 every night since I use both. The L&M produces far better light; it is one fourth the total price of my dyno set up and suffers only in that it requires charging. -- Jay Beattie. Like I’ve said before most of times that I’m riding at night it’s by accident. The few planned times are as I described. So a dyno doesn’t do much for me. Oddly, "riding at night by accident" is one of the main reasons I settled on dyno lights. A big event for me was being on a solo tour in Middle-Of-Nowhere Township, trying to get to a particular state park. It was hillier than I anticipated, dinner in a restaurant took extra long, and surprise, I had to do the last few miles in the dark. So I pulled out the battery light I'd brought and turned it on. The batteries got me to, oh, 3 to 5 miles from the campground. Then nothing. On a two lane country highway. Fortunately, traffic was light. I finished by pulling way off the side of the road whenever a car came. I then installed a dyno on every bike. Since then, there have been countless times I didn't plan on riding in the dark, but had to - meetings that ran long, extra work to get done, having too much fun to leave, etc. It's no problem. My lights are just like those on my car. No preparation needed, just turn them on and they work. I can see that wouldn't be valuable for people who use their bikes differently than I do. As for charging, it’s pretty much routine. I have to charge my phone, my Garmin, my lights and even my watch. Pfft. Battery charge is now an issue. A Garmin and a phone that can last for a 175km ride hS become a thing. Again, we all have different requirements. The fact that we all ride bikes is way cool. Too bad we can’t avoid the bull**** here. and then a thread would look like: Hey! I use a Gamnin! ----- You do? So do I. ---- Wow! I use one too. --- Doesn't everybody use a Garmin? --- So cheap they ought to. --- :-) :-) And it would require so little technical thinking! Win - win! 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." What do you use for lights? How well do they work for you? Why? - Frank Krygowski Exactly. You and I have chosen no-switch always-on dynamos with which we are satisfied based on convenience and dependability with virtually zero maintenance. Heated discussions of amp hours, megalumens and optic patterns may be vaguely interesting but not relevant to my (our?) cycling. 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! -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. Call it frictional losses or rolling resistance, but power is lost rolling a bottle generator against a sidewall beyond that which a hub generator would incur. AND ONCE AGAIN THE INDOMONIBLE TOMMIE PROVES TO THE WORLD that he doesn't know what he is talking about. When Frank is telling us that he only lost on mph at a speed where he is generating almost his entire output capacity my eyes are rolling and so must everyone's. No Tommy, the eyes are rolling because you don't know what you are talking about. -- cheers, John B. |
#298
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Better Braking?
On Tue, 18 Feb 2020 04:48:17 +0000 (UTC), Ralph Barone
wrote: John B. wrote: On Mon, 17 Feb 2020 06:17:01 -0800 (PST), Tom Kunich wrote: On Saturday, February 15, 2020 at 6:50:46 AM UTC-8, AMuzi wrote: On 2/14/2020 10:18 PM, Frank Krygowski wrote: On Friday, February 14, 2020 at 6:34:47 PM UTC-5, AMuzi wrote: On 2/14/2020 5:05 PM, Frank Krygowski wrote: On 2/14/2020 5:47 PM, John B. wrote: On Fri, 14 Feb 2020 21:35:18 -0000 (UTC), Duane wrote: jbeattie wrote: On Friday, February 14, 2020 at 11:35:46 AM UTC-8, Duane wrote: On 2/14/2020 2:23 PM, 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 imagine it depends on what you want. I use a Planet Bike 2w when I'm doing club rides in the evening because it's dark on my ride back home from the start. But I'm not out in the country, only the burbs. I don't need a lot of distance but I need something to show me the potholes in enough time to avoid them. My guess is that a flashlight would probably work in that case. Then you have people riding in the rain, pitch dark, pitch dark rain down steep declines etc. etc. etc. I seriously doubt that there's a one for all solution. In the latter circumstances, a dyno clearly is not the solution. In stormy weather, fast downhill or trail, a bright battery light is best . . . for me, and speaking as someone who owns a dyno and battery lights. I can A/B my dyno and my little all-in-on L&M Urban 800 every night since I use both. The L&M produces far better light; it is one fourth the total price of my dyno set up and suffers only in that it requires charging. -- Jay Beattie. Like I’ve said before most of times that I’m riding at night it’s by accident. The few planned times are as I described. So a dyno doesn’t do much for me. Oddly, "riding at night by accident" is one of the main reasons I settled on dyno lights. A big event for me was being on a solo tour in Middle-Of-Nowhere Township, trying to get to a particular state park. It was hillier than I anticipated, dinner in a restaurant took extra long, and surprise, I had to do the last few miles in the dark. So I pulled out the battery light I'd brought and turned it on. The batteries got me to, oh, 3 to 5 miles from the campground. Then nothing. On a two lane country highway. Fortunately, traffic was light. I finished by pulling way off the side of the road whenever a car came. I then installed a dyno on every bike. Since then, there have been countless times I didn't plan on riding in the dark, but had to - meetings that ran long, extra work to get done, having too much fun to leave, etc. It's no problem. My lights are just like those on my car. No preparation needed, just turn them on and they work. I can see that wouldn't be valuable for people who use their bikes differently than I do. As for charging, it’s pretty much routine. I have to charge my phone, my Garmin, my lights and even my watch. Pfft. Battery charge is now an issue. A Garmin and a phone that can last for a 175km ride hS become a thing. Again, we all have different requirements. The fact that we all ride bikes is way cool. Too bad we can’t avoid the bull**** here. and then a thread would look like: Hey! I use a Gamnin! ----- You do? So do I. ---- Wow! I use one too. --- Doesn't everybody use a Garmin? --- So cheap they ought to. --- :-) :-) And it would require so little technical thinking! Win - win! 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." What do you use for lights? How well do they work for you? Why? - Frank Krygowski Exactly. You and I have chosen no-switch always-on dynamos with which we are satisfied based on convenience and dependability with virtually zero maintenance. Heated discussions of amp hours, megalumens and optic patterns may be vaguely interesting but not relevant to my (our?) cycling. 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! -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am quite aware that friction losses from a hub generator are minor but that isn't so for a sidewall generator because it has to be pressed very tightly against the sidewall to keep it was slipping. So it takes probably two to three times the frictional losses as the light output. Er... Tommy, frictional losses in mechanical devices is: " Friction occurs when two bodies are in contact with each other and have relative motion". However you say " pressed very tightly against the sidewall to keep it was slipping" and if there is no slipping than obviously there is no relative motion and thus no friction. Call it frictional losses or rolling resistance, but power is lost rolling a bottle generator against a sidewall beyond that which a hub generator would incur. Of course there is a power loss but it is not the friction between the generator roller and the tire wall. AND ONCE AGAIN THE INDOMONIBLE TOMMIE PROVES TO THE WORLD that he doesn't know what he is talking about. When Frank is telling us that he only lost on mph at a speed where he is generating almost his entire output capacity my eyes are rolling and so must everyone's. No Tommy, the eyes are rolling because you don't know what you are talking about. -- cheers, John B. -- cheers, John B. |
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Better Braking?
On Tuesday, February 18, 2020 at 9:32:31 AM UTC+1, John B. wrote:
Of course there is a power loss but it is not the friction between the generator roller and the tire wall. Of course there is friction between the generator roller and the tire because the direction of the circumferential speed of the roller is not exactly aligned with that of the tire. Lou |
#300
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Better Braking?
lou.holtman wrote:
On Tuesday, February 18, 2020 at 9:32:31 AM UTC+1, John B. wrote: Of course there is a power loss but it is not the friction between the generator roller and the tire wall. So what it that power loss, John? Of course there is friction between the generator roller and the tire because the direction of the circumferential speed of the roller is not exactly aligned with that of the tire. And there are the conversions from the roller poking into the rotating tire wall, soft generator roller running on metal, or both sides shared. And don't forget wasteful springs moving in the generator mount because the wheel is not perfectly trued. But wait, that's still top secret, we at SpringShine Corp. (Shenzen, Denmark) will be exploiting this effect to introduce WheelPulseLED®, the next big crowdfunded "lossless" project in bicycle lighting. |
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