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#232
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Why do some forks and frames have brake rotor size limits?
See above. And it better rain hard soon because my black/salmon Koolstops are very close to worn down and I certainly will not replace them with new Koolstops. They wanted $17/pair for the MTB version last time I looked. Not going to happen. IME Clarks work just as well, last as long and cost only $4/pair. We'll wait. Post the pic. |
#233
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Why do some forks and frames have brake rotor size limits?
John B. writes:
On Thu, 26 Oct 2017 17:08:10 -0400, Radey Shouman wrote: jbeattie writes: On Wednesday, October 25, 2017 at 8:59:47 AM UTC-7, wrote: On Tuesday, October 24, 2017 at 5:22:03 PM UTC-7, John B. wrote: On Tue, 24 Oct 2017 11:47:12 -0700, Joerg wrote: [ ... ] The reason can be summed up in one word: Rain :-) But last Sunday I started out my "weekend" ride in the rain. It had been raining nearly all night and the roads had a lot of water on them - note we have been having floods here in Bangkok lately - but it appeared that the rain was ending so off I went. Unfortunately my weather forecasting facility wasn't working very well and I rode 20 Km of a 30 Km ride in light rain and flooded roads in many places. I was splashing through water in some places and cars were splashing through (and splashing me) in others. Of course, Sunday is much lighter traffic then on work days but still, Bangkok is rated as one of the cities with the most chaotic traffic in the world, and I did have to stop suddenly several time, on flooded roads with wet wheels and brakes. My brakes worked just as they do in the dry. Back brake stops me somewhat slowly and front brake stops rather suddenly, both brakes together provides best stopping. No long wait after grabbing a brake lever although I did think of you with your stopping problems and I have the feeling that the brake lever pressure might be a tiny bit more to stop in the rain but if it was it was so little that it couldn't be quantified. But of course I am using quality brake pads. Why it costs me US$12.12 a wheel just for pads alone.... but they do last a year or more. This is something I just can't understand. Indeed there is a millisecond or two delay for the brake shoe to excise the water directly in front of the initial application of the brake but after the brake shoe touches the rim it pushes any water in the way off without floating the shoe above it. I see no reason whatsoever for disk brakes and their complications even on most MTB's since a good V-Brake is longer lasting, just as effective, cheaper and doesn't require special wheels and frame and fork changes. If you ride a lot in the rain and use a rim brake, you might go through a front rim every 1-2 years -- at least based on the experience of one of my commuter cohorts who just switched to discs. And the slowly dying rims generate some really messy black sludge, at least in my experience. I'm not sure why the "wax your chain to stay clean" cohort hasn't noticed. It is probably heresy to mention it, but some people wash their bikes, particularly after riding in the rain. Amazing how easily all that black sludge washes off with soap and water :-) I was thinking particularly of an incident of a few years ago. I rode 80 miles from my house to a b & b on the Quabbin reservoir in central Mass., to go see the reservoir, and one of the ghost towns that was not completely drowned. As it happened, it rained all day. When I got there, the landlady was visibly peeved, because I was somewhat later than I had planned, on account of farting around in the morning thinking the rain might stop, and of riding like a little old lady. I suppose I should have called her, but I didn't even think of it. She said, "Where's your bicycle? You can bring it right it." So I did, and we watched it drip nasty black aluminum sludge on the floor as she chatted me up. Good times. -- |
#234
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Why do some forks and frames have brake rotor size limits?
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#235
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Why do some forks and frames have brake rotor size limits?
On Mon, 30 Oct 2017 07:42:50 -0700, Joerg
wrote: On 2017-10-29 18:02, John B. wrote: On Sun, 29 Oct 2017 07:59:34 -0700, Joerg wrote: On 2017-10-28 17:18, John B. wrote: On Sat, 28 Oct 2017 08:09:28 -0700, Joerg wrote: On 2017-10-27 17:11, John B. wrote: On Fri, 27 Oct 2017 06:58:27 -0700, Joerg wrote: On 2017-10-27 01:11, John B. wrote: On Wed, 25 Oct 2017 07:53:11 -0700, Joerg wrote: On 2017-10-24 17:21, John B. wrote: On Tue, 24 Oct 2017 11:47:12 -0700, Joerg wrote: On 2017-10-24 07:27, wrote: On Tuesday, October 24, 2017 at 2:19:48 AM UTC-7, John B. wrote: On Mon, 23 Oct 2017 10:09:20 -0700, Jeff Liebermann wrote: On Mon, 23 Oct 2017 12:48:29 +0700, John B. wrote: On Sun, 22 Oct 2017 20:51:15 -0700, Jeff Liebermann wrote: On Mon, 23 Oct 2017 07:02:08 +0700, John B. wrote: But re disc brake cooling F1 car brakes appear to work with the discs red hot. In the 1,000 degree (F) range. And they use Carbon Fiber discs too :-) And everyone knows that CF is better. "Thermal Conductivity of Carbon Fiber, and other Carbon Based Materials" http://www.christinedemerchant.com/carbon_characteristics_heat_conductivity.html "So...Is Carbon Fiber a good heat conductor? As usual the answer is "it depends." The short answer is NO not when regular carbon fiber is made up in regular epoxy and expected to conduct heat across the thickness. IF a highly carbonized pan fiber with graphite or diamond added, is measured for heat transmission in the length of the fiber it is very good and can rival and exceed copper." On the other hand, they seem to work pretty well :-) See https://www.youtube.com/watch?v=h5JcHAEmIYM for a visual indication of heat dissipation. :-) Impressive. I'll assume it's a carbon-carbon rotor, since all F1 cars seem to using them. Undoubtedly so. But if the advantage of "carbon" bikes can be extolled that a carbon-carbon frame must have twice the bragging rights :-) http://www.racecar-engineering.com/technology-explained/f1-2014-explained-brake-systems/ (4 pages) "A typical road car uses a cast iron brake disc with an organic brake pad. In an F1 car, though, the same material is used for both disc and pad, and this material is known as carbon-carbon - a significantly different material to the carbon-fibre composites used in the rest of the car" In other words, the F1 brakes are NOT made from CF. Some detail on Formula 1 brakes: https://www.youtube.com/watch?v=ev6XTdlKElw Fun destroying brakes: https://www.youtube.com/watch?v=KslGsXMgmqg The brake starting at 4:45 sure looks like CF but I'm not sure. Maybe twin disk brakes would be easier? http://nuovafaor.it//public/prodotto/75/nccrop/DOPPIO_FRENO_CROSS_ENDURO.jpg https://i.ytimg.com/vi/Pvwj-WWlKkg/maxresdefault.jpg https://gzmyu4ma9b-flywheel.netdna-ssl.com/wp-content/uploads/2011/09/Gatorbrake-dual-hydraulic-front-disc-brakes-carbon-rotors01.jpg https://lh4.googleusercontent.com/-cDfAFWrGR6Q/VHKPsm-f6YI/AAAAAAAAX10/2FCyj87xs0g/s640/14%2520-%25201.jpg https://www.minibikecraze.co.uk/wp-content/uploads/bs0978.jpg https://endless-sphere.com/forums/viewtopic.php?f=28&t=56268 Given the coefficient of friction between a 1.25" wide rubber tire (32mm) and a wet road probably dragging the feet will work. :-) Joerg's experience is with full suspension MTB's. These things are incredibly heavy and long wheelbased. He has his judgement of disks and it is no doubt quite accurate for his experience and riding. I have disks on a much lighter and shorter wheelbased bike. I know the failings up close and personal. I simply cannot imagine WHY a person would want a more complicated system than that offered by the Campy Skeleton brakes. The reason can be summed up in one word: Rain :-) But last Sunday I started out my "weekend" ride in the rain. It had been raining nearly all night and the roads had a lot of water on them - note we have been having floods here in Bangkok lately - but it appeared that the rain was ending so off I went. Unfortunately my weather forecasting facility wasn't working very well and I rode 20 Km of a 30 Km ride in light rain and flooded roads in many places. I was splashing through water in some places and cars were splashing through (and splashing me) in others. Of course, Sunday is much lighter traffic then on work days but still, Bangkok is rated as one of the cities with the most chaotic traffic in the world, and I did have to stop suddenly several time, on flooded roads with wet wheels and brakes. My brakes worked just as they do in the dry. Back brake stops me somewhat slowly and front brake stops rather suddenly, both brakes together provides best stopping. No long wait after grabbing a brake lever although I did think of you with your stopping problems and I have the feeling that the brake lever pressure might be a tiny bit more to stop in the rain but if it was it was so little that it couldn't be quantified. But of course I am using quality brake pads. Why it costs me US$12.12 a wheel just for pads alone.... but they do last a year or more. It seems Californian rain and Thai rain aren't the same. When it rains heavily and I have to do a surprise emergency stop after not having used the brakes for a while there is 1-2sec of nada, absolutely nothing. It makes no difference whatsoever whether I use $17 high-falutin Koolstop rain-rated pads or $4 Clarks pads. The experience of other riders around here and in this NG is similar. Which, to be honest, I find a little mystifying as I've had pretty constant success with conventional brakes. Frankly, I can't believe this is solely because I'm somehow so uniquely skilled or that y'all are all in the awkward squad I do see a number of people here and many who are not here who seem to have ridden for years using conventional brakes without complaint and some of the blogs I read don't even talk about brakes. Dave Moulton, for example. An old fellow, used to race bikes, came to the U.S. in about 1979 and built frames commercially for years, now retired, has one entry in his blog about brakes - "centering side pull brakes". Another blog from the long distance side of the bicycleing world, The Blayleys, who are into Audex's and who apparently each ride in the neighborhood of 10,000 miles annually, mentions Vee brakes in reference to a Tandem while a photo of them on a tandem on their web page shows disc brakes. On the other hand, when she discusses a "good brevet bike she simply says that the "brakes must clear the fenders and probably long reach caliper brakes will suffice". In short, it seems that brakes just don't seem to be a hot subject in much of the cycling fraternity. To a large part that is because most cyclist will not ride in driving rain. Some do and those know exactly how that delay with rim brakes feels. Occasionally it is called "free fall" because that's how it feels like. Well, the Blayleys state that the husband, John, has ridden 10 - 17 thousand miles a year for the past 25 years and the wife, Pamela, has ridden from 10 - 14 thousand miles a year for the past 20 years, or another way to put it might be that together they have ridden from 20 - 30 thousand miles a year for the past 20 years. Somehow I suspect that they may have encountered rain in that period. And grandpa has driven his cars without safety belts yet survived ... Well, since you mentioned it. My two grandfathers, neither of whom ever had a road accident. One died at 92 and the other at 87. My father never had a road accident although he did get a speeding ticket once, died at 87. My mother had one "accident", a guy ran a red light and tee-boned her car, no speeding tickets, died at 86. All deaths were considered "natural". Do you really believe that safety belts would have benefited them? Counting on luck alone is not smart. The father of a friend's wife died from the consequences of a minor fender bender at an intersection because he didn't wear a belt. That accident was 100% survivable. Or would have been ... So one of your friends died in a traffic accident and four of my ancestors never had an accident at all. Thus safety belts are a good idea? Yes, they are. Ask any ER doctor who is old enough to remember the days before safety belts and before motorcycle helmets. The folks who do or did emergency surgery on traffic accident victims. My wife used to work there so we know. I think I'd also have to ask, "how many if these people were in violation of the traffic code when they were injured?" I was thinking back over the motorcyclists I've known who were injured riding their bikes and every one was violating the traffic code. I have to wonder, if rather then a seat belt law they had made a "obey the law" law what would have been the outcome? -- Cheers, John B. |
#236
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Why do some forks and frames have brake rotor size limits?
On 10/30/2017 10:04 PM, John B. wrote:
On Mon, 30 Oct 2017 07:25:14 -0700 (PDT), wrote: You rarely have to worry someone is actually going to run you over. After all if might get blood on their car that they'd have to wash off. But the continuous threats are tiring. When I get back from a long city ride - say my home down to Palo Alto along Hesperian then back again - some 50 miles - I will be threatened at least two dozen times with cars trying to nudge me off the road. Even with open lanes they could easily pass in. Another thing is that you will be riding along and a car will come up behind you fast, swerve around you and turn directly into a driveway that causes you to slam on the brakes. Usually a store or something. I can only say that the U.S. must be different. I've ridden in Japan, Indonesia, Singapore, Malaysia and Thailand and have never, repeat NEVER, had anyone threaten me, either by word or action. I also rode in New Hampshire and Southern California, but that was a long time ago and I can't be sure but I certainly don't remember any acts that were threatening. I can only say that other parts of the U.S. must be different, because what Tom describes almost never happens to me. Although my "other parts of the U.S." statement needs some modification, since I've ridden all the way across it, and ridden at least a little in 47 states so far. The last irritating incident that happened to me was three weeks ago, on a 50+ mile ride. Ohio has a new law requiring three feet passing clearance. One car passed closer than that when there was plenty of room to go around. But as someone said, I probably shouldn't attribute to malice what can be adequately explained by stupidity. If the police were to ticket these people the state would never again have to raise taxes. And it would have the side effect of increasing road safety. But the drivers would not stand for it. Locally one of the people who was caught by a red light camera wrote a letter to the editor of the local paper. He was outraged that they were using cameras to record miscreants. There were a dozen follow-ups by others agreeing with him and not ONE comment to the contrary. In our area, the camera issue was speeding, not red lights. Yes, there were online complaints about the fact that the cops were giving tickets for being 13 mph over the 50 mph limit on the city-center freeway. But here, to counter the over-privileged bitching, there were several individuals posting "Don't be stupid, just drive slower." I was one of those. I mentioned that the time saved by speeding had to be less than three minutes. -- - Frank Krygowski |
#237
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Why do some forks and frames have brake rotor size limits?
On 10/30/2017 6:53 PM, Joerg wrote:
On 2017-10-29 17:09, Frank Krygowski wrote: ... let me repeat: I've had some motorists act displeased when I've ridden at lane center. I've never had one run me over. I've never known another cyclist who had that happen. I knew two personally who have been hit from behind. They survived but one lost a kidney and the other had a ruptured spleen. Then there was the woman here who got rear-ended in the right lane at high speed. Died. Numerous others down in the valley, including an off-duty police officer who was catapulted off his road bike and died. And I can double check my list, but I think it's now up to nine friends who were killed in motor vehicle accidents. Zero on bicycles. We can trade anecdotes (and you frequently do) but I give more credence to unbiased data. It doesn't pay to be timid. Man up. Why take the risk when there are alternatives such as this? https://goo.gl/maps/XJk1gMRC2eA2 Here's why I "take the risk," Joerg. First, the risk of being hit while riding lane center is extremely low. Most of those hit that way seem to be unlit cyclists riding at night, probably drunk or nearly so. Data's a bit soft, but that does seem to be what it shows. But more important: If I waited for "alternatives" such as the one you show to be built, I would have missed about 45 years of enthusiastic adult riding. I'd have missed riding in about a dozen different countries, 47 states and hundreds of different towns and cities. I wouldn't have been able to ride my bike to work at four different jobs. I'd have missed wonderful vacations with my family, and I'd have missed making at least a hundred good cycling friends. I know many people have bought the "Danger! Danger!" mantra and never leave the nice, safe (and horridly boring) bike path. I chose instead to learn to be competent on ordinary roads. And I'm damned glad I did. -- - Frank Krygowski |
#238
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Why do some forks and frames have brake rotor size limits?
On Sat, 28 Oct 2017 07:59:40 +0700, John B.
wrote: Riding in one of the crew busses at the mine I don't remember the jake brake being excessively loud, and as the alternate on most of that road was "straight down a thousand feet" probably wouldn't have minded anyway. When you're trying to sleep or study, any loud noise is too loud. "Jake brake contest 2014 (Full)" https://www.youtube.com/watch?v=pHTrEwRk0MU The winner delivered about 130dB SPL which is what a jet taking off produces at 100 meters: http://personal.cityu.edu.hk/~bsapplec/Fire/SPL01.jpg http://elephanttech.com/wp-content/uploads/2013/11/decibel-levels-ear-plugs.jpg -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#239
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Why do some forks and frames have brake rotor size limits?
On Mon, 30 Oct 2017 22:52:12 -0400, Frank Krygowski
wrote: On 10/30/2017 10:04 PM, John B. wrote: On Mon, 30 Oct 2017 07:25:14 -0700 (PDT), wrote: You rarely have to worry someone is actually going to run you over. After all if might get blood on their car that they'd have to wash off. But the continuous threats are tiring. When I get back from a long city ride - say my home down to Palo Alto along Hesperian then back again - some 50 miles - I will be threatened at least two dozen times with cars trying to nudge me off the road. Even with open lanes they could easily pass in. Another thing is that you will be riding along and a car will come up behind you fast, swerve around you and turn directly into a driveway that causes you to slam on the brakes. Usually a store or something. I can only say that the U.S. must be different. I've ridden in Japan, Indonesia, Singapore, Malaysia and Thailand and have never, repeat NEVER, had anyone threaten me, either by word or action. I also rode in New Hampshire and Southern California, but that was a long time ago and I can't be sure but I certainly don't remember any acts that were threatening. I can only say that other parts of the U.S. must be different, because what Tom describes almost never happens to me. Although my "other parts of the U.S." statement needs some modification, since I've ridden all the way across it, and ridden at least a little in 47 states so far. The last irritating incident that happened to me was three weeks ago, on a 50+ mile ride. Ohio has a new law requiring three feet passing clearance. One car passed closer than that when there was plenty of room to go around. But as someone said, I probably shouldn't attribute to malice what can be adequately explained by stupidity. If the police were to ticket these people the state would never again have to raise taxes. And it would have the side effect of increasing road safety. But the drivers would not stand for it. Locally one of the people who was caught by a red light camera wrote a letter to the editor of the local paper. He was outraged that they were using cameras to record miscreants. There were a dozen follow-ups by others agreeing with him and not ONE comment to the contrary. In our area, the camera issue was speeding, not red lights. Yes, there were online complaints about the fact that the cops were giving tickets for being 13 mph over the 50 mph limit on the city-center freeway. But here, to counter the over-privileged bitching, there were several individuals posting "Don't be stupid, just drive slower." I was one of those. I mentioned that the time saved by speeding had to be less than three minutes. In W. Australia, and probably the rest of the country, they had "speed Cameras" which were mounted on portable tripods along roads ranging from city streets to "way out in the country". I was told by my mate, who's daughter was employed by the Perth Police in a clerical position, that these cameras communicated with the police in some manner and transmitted data on speeding cars which the police computer turned into a speeding ticket which was mailed to your house. The attitude seemed to be "stay under the speed limit" rather then "I'm being persecuted". But the U.S. attitude, which admittedly I only see posted in Internet articles, about some sort of leeway on obeying laws seems odd. If it is O.K. to drive 15 mph over the posted limit then why a lower posted limit. Why not simply a posted 65 mph limit? One wonders, is it O.K. to steal if it is only a little? Or even commit murder... in a small way? -- Cheers, John B. |
#240
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Why do some forks and frames have brake rotor size limits?
On Mon, 30 Oct 2017 20:28:32 -0700, Jeff Liebermann
wrote: On Sat, 28 Oct 2017 07:59:40 +0700, John B. wrote: Riding in one of the crew busses at the mine I don't remember the jake brake being excessively loud, and as the alternate on most of that road was "straight down a thousand feet" probably wouldn't have minded anyway. When you're trying to sleep or study, any loud noise is too loud. On the other hand is the alternate is a 1,000 ft drop off the side of the mountain it has a sort of comforting sound :-) "Jake brake contest 2014 (Full)" https://www.youtube.com/watch?v=pHTrEwRk0MU The winner delivered about 130dB SPL which is what a jet taking off produces at 100 meters: http://personal.cityu.edu.hk/~bsapplec/Fire/SPL01.jpg http://elephanttech.com/wp-content/uploads/2013/11/decibel-levels-erar-plugs.jpg Don't get too carried away with those decibel charts. The sound of a jet engine at full throttle is very noticeably different depending on where you are standing. In an engine test cell where you can walk around the running engine standing a distance in front of the engine results in very much lower sound levels then standing the same distance behind the engine. -- Cheers, John B. |
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