|
|
|||||||
|
|
Thread Tools | Display Modes |
| Ads |
|
#32
June 2nd 05, 11:59 PM
|
|||
|
|||
Cleaning Glue off of Tire Sidewalls?
someone sniped anonymously:
Some porus base tapes don't need a dry layer of glue applied to them beforehand. The Deda Olimpico (my favorite racing tire) is one of those. Just put a light layer on the rim, let it set for 20 to 40 minutes, and mount the tire. Insanity!! Really tho, one light layer onto the rim and none on the tire=tire roll. In ~32 years of riding tubulars daily (having switched to and from clinchers 3 times) I've yet to pre-glue a base tape. Only once in that time have I had a problem with adhesion and that was with a Clement Criterium Cotton which had a thick layer of slick latex over its base tape. OK, so your an old fart and still don't know what kind of base tape you are looking at. The only reason pre-glueing base tape may be prudent, and then only with certain porus/unsealed base tapes, is so the solvent fumes from drying rim glue doesn't compromise the tire-to-base tape adhesion. It has nothing to do with tire-to-rim adhesion. aka "porous" "porus/unsealed base tapes" are ones on which hard glue or shellac can be used. These adhesives do not hold on coated base tapes but then few people use "Tipo Pista" hard glue. Just the same, tire manufacturers give the user the option by offering bare cloth base tapes. If you are paranoid, and do pre-glue base tapes, be sure to use a _very_ thin layer. Too much glue is worse than too little. It's like solder in that you only need enough to fill the gap. "Very" is a useless word in this and most contexts because it is ill defined and dilutes the adverb/adjective it modifies. Get with quantifiable dimensions. http://www.sheldonbrown.com/brandt/m...-tubulars.html Sheldon Brown is wrong. I guess you can't read but the piece cited isn't from Sheldon Brown. He only furnishes the web space for that article. My experience is that the best bond between tire and rim occurs when the last layer of glue is still relatively wet upon application. (Yes, it is more messy.) This dovetails with Marquis's experience that the glue layer on the tire is probably unnecessary. A layer of wet cement will soak into the base tape more uniformly and improve the bond; the dry "contact cement" does not have the benefit of glue flow to increasive the effective adhesive surface. (Effective adhesive surface is defined operationally as surface with glue on it that is actually adhering to the mating tire surface.) I guess if you never brake hard enough to heat your rims you may have had that experience, but pressure sensitive glues are mobile and squirm all over so that the tire seats where it sinks in under flexing. If you inspect old rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire eroded the aluminum rim. (Brown's comments are also obsolete about different tubular cement brands.) They are not "Brown's comments' and the glues mentioned are similar to other favorite brands. Besides they are still on the rare item market. The sticky pregluing of the base tape is a good idea for a spare tire, but treating contemporary tubular tire glue as a purely contact cement does not create the strongest bond. I don't think you ride tubulars or you would have plenty of used tires that have glue on them. The way you describe this, it seems you theoretically take a new tire along as a spare. People who ride tubulars don't follow that regimen. I don't have numbers on how much force is required to remove a tire using these two methods, but I do know that the wet layer bond using Vittoria Mastik is extremely difficult to break by hand (on the road I usually pull out an allen wrench that I work under the tire, but I'm thinking about carrying an aluminum tire lever, if I can find one, for that purpose), while the contact cement method is easily pried off by hand. That is an objective observation. Who gives a hoot how much force. The glue only prevents tire creep, the constriction of the casing under pressure holds the tire on... with plenty of force. The calculation of that is in "the Bicycle Wheel". Would be interested to see a test of the difference in rolling resistance between the two gluing methods. Given your own test results 20+ years ago comparing road and track glues, it seems a certainty to me that contemporary road glue, used in combination with gluing technique designed to give the strongest bond (as opposed to being easily removable in case of a flat), is almost certain to result in the least rolling resistance. So where are your tests? I suppose you believe Sheldon did those tests as well. I wouldn't be calling someone an "old fart" if I were you. "Old fart" is a state of mind, not chronological years. 
|
|
#33
June 3rd 05, 01:56 AM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
|
|
#34
June 3rd 05, 02:27 AM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
someone sniped anonymously:
I guess you can't read but the piece cited isn't from Sheldon Brown. He only furnishes the web space for that article. I noticed that your name was on it after I had read the substance of the article and responded to it. I considered replying to my own article to correct the attribution but thought it was too trivial, because after all, Sheldon is repsonsible for the content of his website. I guess if you never brake hard enough to heat your rims you may have had that experience, but pressure sensitive glues are mobile and squirm all over so that the tire seats where it sinks in under flexing. With Vittoria Mastik the rim can be heated to a point where you can't touch it and it still maintains more strength than the glues you used in your day do at their optimal operating temp. But even you admitted in a previous post that extreme braking conditions are required to heat rims to that degree, that usually wind resistance provides enough braking that the rim does not need to reach that temperature. You are fooling yourself if you believe that. Glues haven't changed all that much and if they have they are on the border of not being useful for a spare tire if they are not soft enough when at room temperature to hold. If heating them doesn't affect them then you have a glue that is useless because all pressure sensitive glues are thermally affected. If you inspect old rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire eroded the aluminum rim. Old is right. Because if they are new rims (or even old rims) using contemporary glue applied as I suggested, they will not squirm that way, or as much. OK, so let's rephrase that: If you inspect your used rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire has eroded the aluminum rim. (Brown's comments are also obsolete about different tubular cement brands.) They are not "Brown's comments' and the glues mentioned are similar to other favorite brands. Besides they are still on the rare item market. Not according to recent testing. Those glues don't come close to Conti or especially VM in strength. This is the same old story we've been hearing every year throughout the days when people still rode tubulars. It's only how much you believe the ad copy. I don't think you ride tubulars or you would have plenty of used tires that have glue on them. Unlike you, I have ridden tubulars almost exclusively for the last 30+ years. Oh? How do you know how many years I rode tubulars? As I have mentioned, in the days when there were no useful racing clinchers, I held Wednesday evening tubular repair sessions for the local racers. The items in the FAQ on tubulars is all well tested. The way you describe this, it seems you theoretically take a new tire along as a spare. People who ride tubulars don't follow that regimen. Sometimes I do, sometimes I don't. What I don't do is keep a bunch of extra tubulars lying around, and what I also don't do is pull off a glued tire to make it a spare and replace it with a new one. To be perfectly honest, I don't pre-glue *new* spares either, but I realize that I probably should. Sometimes I will put on a used (pre-glued) spare, buy a new tire and put it under the saddle, and ride around on the spare for a couple of weeks before I get around to gluing it down, if it is a rear tire. And then my decision about which tire to glue and which to keep as a spare will be based on different factors like which is the better tire and what are their relative conditions. So no, I don't follow a regimen. Somehow your scenario doesn't make sense. When you have a flat or two, you must patch them on the road and re-mount them if you don't have patched tubulars at home. Form years of experience, most riders have at least two tires as spares that resulted from a home repair while two other tires are on the bicycle. Since most riders have more than one set of wheels, there are at least two spares in reserve. I don't visualize how you handle this but it seems hypothetical. I don't have numbers on how much force is required to remove a tire using these two methods, but I do know that the wet layer bond using Vittoria Mastik is extremely difficult to break by hand (on the road I usually pull out an allen wrench that I work under the tire, but I'm thinking about carrying an aluminum tire lever, if I can find one, for that purpose), while the contact cement method is easily pried off by hand. That is an objective observation. Who gives a hoot how much force. That's the whole point- "how much force" is what resists the damn tire rolling off. You seemed to think it important to some degree since in the FAQ you point out that inflation is what you think is the force keeping the tire on the rim. Well that isn't the point. Tires don't roll as you imagine. They are held in place by inflation constriction and kept from creeping significantly by the glue. Even with rim cement, they move. I think that if you took some demanding descents around here, you too would have to reverse your front wheel to make the tire creep back to where the stem is again radial from reverse creep. This is old hat and hasn't changed. The glue only prevents tire creep, the constriction of the casing under pressure holds the tire on... with plenty of force. Wrong, and it's easily verified. A fully inflated but unglued tire can be pulled off a rim by hand; a properly glued tire cannot. I can pull of a fully glued and inflated tire. So what? The calculation of that is in "the Bicycle Wheel". The calculation is wrong if it based on the gluing method described on Brown's site. I don't think you know with what your are disagreeing. The constriction force is correct and is valid for tubulars and clinchers with bias ply cords. Just slow down a bit and review what is being discussed. Would be interested to see a test of the difference in rolling resistance between the two gluing methods. Given your own test results 20+ years ago comparing road and track glues, it seems a certainty to me that contemporary road glue, used in combination with gluing technique designed to give the strongest bond (as opposed to being easily removable in case of a flat), is almost certain to result in the least rolling resistance. So where are your tests? Don't have them but extrapolating from yours and the recent testing with tubular glues I think it is a reasonable hypothesis. Your ranting has certainly done nothing to cast doubt on it. I can't do much with that nor can anyone else. I suppose you believe Sheldon did those tests as well. No, I doubt that any regular reader of this ng could *possibly* escape the fact that you and Avocet did the tests. SO what is it that you don't believe? I wouldn't be calling someone an "old fart" if I were you. "Old fart" is a state of mind, not chronological years. Ain't *that* the truth. Like I said. aka "as I said". I take it English is a second language for you.
|
|
#35
June 3rd 05, 06:36 PM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
wrote:
someone sniped anonymously: With Vittoria Mastik the rim can be heated to a point where you can't touch it and it still maintains more strength than the glues you used in your day do at their optimal operating temp. But even you admitted in a previous post that extreme braking conditions are required to heat rims to that degree, that usually wind resistance provides enough braking that the rim does not need to reach that temperature. You are fooling yourself if you believe that. Glues haven't changed all that much The strongest glues did not exist when you did your testing. and if they have they are on the border of not being useful for a spare tire if they are not soft enough when at room temperature to hold. So which is it? Have they or have they not changed "all that much"? Since I happen to think that the data supports the latter, I will grant you this: they may not be the best glues to use for a spare tire. That would match my experience that the contact cement method of gluing tires that you recommend does not create the strongest bond with VM. OK, so let's rephrase that: If you inspect your used rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire has eroded the aluminum rim. I have noticed taking VM-glued tires off and only seeing the white glue, but I admit that doesn't mean anything. The real question is whether the degree of squirm is as great as with the old glues. Some squirm would produce some oxide; a quarter as much squirm might produce the same amount of oxide if the tire was used 4x as long- very, very difficult to draw any meaningful conclusions from the presence of aluminum oxide without a very carefully controlled test procedure. They are not "Brown's comments' and the glues mentioned are similar to other favorite brands. Not according to recent testing. Those glues don't come close to Conti or especially VM in strength. This is the same old story we've been hearing every year throughout the days when people still rode tubulars. It's only how much you believe the ad copy. I don't read ad copy, I don't buy cycling mags. Does anyone actually advertise tubular glues? I am basing my "story" on the testing shown at: http://www.engr.ku.edu/~ktl/bicycle/bicycle.html Unlike you, I have ridden tubulars almost exclusively for the last 30+ years. Oh? How do you know how many years I rode tubulars? I made no reference to how long you rode tubulars, I don't know how many years you rode them, and I don't care. What I *do* know is that you haven't ridden them with any regularity for about thirty years, and I know this because you have told us this over and over here on this ng. As I have mentioned, in the days when there were no useful racing clinchers, I held Wednesday evening tubular repair sessions for the local racers. The items in the FAQ on tubulars is all well tested. The stuff in the FAQ is dated. Sometimes I do, sometimes I don't. What I don't do is keep a bunch of extra tubulars lying around, and what I also don't do is pull off a glued tire to make it a spare and replace it with a new one. To be perfectly honest, I don't pre-glue *new* spares either, but I realize that I probably should. Sometimes I will put on a used (pre-glued) spare, buy a new tire and put it under the saddle, and ride around on the spare for a couple of weeks before I get around to gluing it down, if it is a rear tire. And then my decision about which tire to glue and which to keep as a spare will be based on different factors like which is the better tire and what are their relative conditions. So no, I don't follow a regimen. Somehow your scenario doesn't make sense. When you have a flat or two, you must patch them on the road and re-mount them if you don't have patched tubulars at home. Nonsense. I mount the spare, take the flat home and either repair it or not. Then the repaired tire, or a new replacement tire becomes the spare for the next ride. You only need three functional tires in this "regimen" unless you get two flats in one ride, which has only happened once that I remember, although I have a vague feeling that it may have happened another time in the distant past. Form years of experience, most riders have at least two tires as spares that resulted from a home repair while two other tires are on the bicycle. Since most riders have more than one set of wheels, there are at least two spares in reserve. I don't visualize how you handle this but it seems hypothetical. I have spare wheels; they don't have tires mounted on them. That hasn't really been a need since I last raced years ago. That's the whole point- "how much force" is what resists the damn tire rolling off. You seemed to think it important to some degree since in the FAQ you point out that inflation is what you think is the force keeping the tire on the rim. Well that isn't the point. Tires don't roll as you imagine. They are held in place by inflation constriction and kept from creeping significantly by the glue. Even with rim cement, they move. Inflation constriction certainly helps to keep them in place; that doesn't prove that it is the primary force holding them on the wheel when using the best contemporary glues. I think that if you took some demanding descents around here, you too would have to reverse your front wheel to make the tire creep back to where the stem is again radial from reverse creep. This is old hat and hasn't changed. Given that VM is a relatively new glue, and proven that at high rim temperatures is retains more strength than the old glues did at optimal temperatures, it is clear that it *has* changed. I can pull of a fully glued and inflated tire. So what? I'd be willing to wager that if I carefully glued a tire on with VM and pumped it up, you *couldn't* pull it off by hand, but, what the hell, I'm sure there are people out there stronger than me that could, and maybe you're one of them. I don't think you know with what your are disagreeing. The constriction force is correct and is valid for tubulars and clinchers with bias ply cords. Just slow down a bit and review what is being discussed. You're right; I didn't read it- no need to: if it says that constriction force acts to prevent a tubular from coming off the rim, I'm sure it's right; if it purports to prove that it is the only significant way that a tubular is held onto a rim, it is wrong, and I know it is wrong because I have personal experience comparing constriction force to VM glue as a way of holding the tire on the rim. There is no doubt: the VM bond is stronger. No calculation, however elegant, can be right if it does not describe reality. In fact, your own testing years ago suggests that I may be right. Just consider the possibility that a road glue may have been developed that matches the bond strength of old track glue. If that has happened, and the above referenced tests indicate that it has, then everything that I have argued here follows from your own tests. SO what is it that you don't believe? I don't believe you know what you are talking about. I don't believe you are capable of analyzing new data on this subject because you have too much emotional investment in your old experience with obsolete materials. I wouldn't be calling someone an "old fart" if I were you. "Old fart" is a state of mind, not chronological years. Ain't *that* the truth. Like I said. aka "as I said". I take it English is a second language for you. 780 GRE verbal. No one says "as I said" in this context, especially not in a paragraph with the word "ain't".
|
|
#36
June 3rd 05, 07:45 PM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
someone sniped anonymously:
With Vittoria Mastik the rim can be heated to a point where you can't touch it and it still maintains more strength than the glues you used in your day do at their optimal operating temp. But even you admitted in a previous post that extreme braking conditions are required to heat rims to that degree, that usually wind resistance provides enough braking that the rim does not need to reach that temperature. You are fooling yourself if you believe that. Glues haven't changed all that much The strongest glues did not exist when you did your testing. and if they have they are on the border of not being useful for a spare tire if they are not soft enough when at room temperature to hold. So which is it? Have they or have they not changed "all that much"? Since I happen to think that the data supports the latter, I will grant you this: they may not be the best glues to use for a spare tire. That would match my experience that the contact cement method of gluing tires that you recommend does not create the strongest bond with VM. If they have then they won't stick again with a spare tire. You can't have it both ways. Either it's a permanent one-use glue or it is a tacky one that accepts resuse for changing a tire. The best glues were available 30 years ago just as they are today. Glues for new uses have been developed since but for reusable rim glues, there has been no advance. Besides, hard glue for tires seem, from the complaints on this NG, practically no longer available. OK, so let's rephrase that: If you inspect your used rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire has eroded the aluminum rim. I have noticed taking VM-glued tires off and only seeing the white glue, but I admit that doesn't mean anything. The real question is whether the degree of squirm is as great as with the old glues. Some squirm would produce some oxide; a quarter as much squirm might produce the same amount of oxide if the tire was used 4x as long- very, very difficult to draw any meaningful conclusions from the presence of aluminum oxide without a very carefully controlled test procedure. Oh BS! There wasn't a wheel that was ridden in the local mountains that didn't have significant creep on steep, hard braking descents. If your tires come off lily white I doubt that you demand much from your glue. What happens to your spares when they are folded? Does the glue stick to itself and need to be pulled apart to open the tire for mounting? This whole picture doesn't make sense. They are not "Brown's comments' and the glues mentioned are similar to other favorite brands. Not according to recent testing. Those glues don't come close to Conti or especially VM in strength. This is the same old story we've been hearing every year throughout the days when people still rode tubulars. It's only how much you believe the ad copy. I don't read ad copy, I don't buy cycling mags. Does anyone actually advertise tubular glues? I am basing my "story" on the testing shown at: http://www.engr.ku.edu/~ktl/bicycle/bicycle.html Selecting one of these items that harp on tire roll-off as if that were the big threat, I find the temperature one most revealing in its lack of field experience. Here again, tire roll-off is the thrust rather than the more serious one of linear creep that piles the tire up against the stem and causes a blowout. No mention of this is made, indicating that these folks don't descent hard or have any idea of the real hazard of tubulars that has plagues them for a long time. In the days if yore, when many of the major Alpine passes were unpaved, descending with continuous braking was the norm and caused major tire creep. Beyond that, they talk of 70 degC when more than 100 degC is common. As I have related, steam hissing out of the stem hole in the rim alerted me to the higher temperatures caused by braking, after riding in snow for a longer distance. There seems to be no mention of the re-usability of the glue on rim and tire for mounting a spare. Hard glue of old did a better job than these in that respect and they had no thermal sensitivity to speak of. Heat was one of the main culprits in the usefulness of tubulars. # TUBULAR TIRES: ADHESIVES AND PRACTICE # PART 6 # Adhesive Performance at Higher Temperatures # C. S. Chip # On high speed descents, a rider may apply sufficient braking to heat # the rims to high enough temperatures such that touching them would # burn - nominally 60 oC (140 oF). While expert descenders may apply # their brakes more prudently resulting in less heating, rims will # still heat to temperatures substantially above ambient. Suppose a # clincher tire is inflated to 100 lbf/in2 (gauge) at a temperature of # 21 oC (70oF). If the tire temperature were to rise to 60 oC (140 # oF), the pressure would rise to 115 lbf/in2 (gauge) in the tire, a # pressure rise of only 1 bar. This would not stress the tire/rim # clinch assuming good condition of the tire and rim. The likelihood # of a blowout due to over-pressure alone is nil. # If a tubular tire is used and subject to the same heating, the # pressure rise would be equivalent. However, the interface between # the tire and the rim is no longer a rim hook and tire bead. The # interface is an adhesive. So while the tubular is unlikely to # blowout due to the temperature rise, if the adhesive properties # change with temperature, the tire may be more prone to roll-off. If # the high temperature is experienced during high-speed, curving # descents which place severe lateral load on the adhesive and if the # adhesive performance degrades, the likelihood of roll-off increases # and this could lead to serious rider injury. # Tubular tire - rim combinations are attractive for their light # rotating mass and low weight. Riders will continue to select them # because of these properties. Proper adhesive selection and proper # application are necessary to minimize the potential for roll-off. # Given the temperature rise due to braking during descents, the # subsequent lateral stress placed on the adhesive bonds in corners # and slides and the potential for serious injury to the rider, it is # important for the mechanic to know how the adhesive will perform. # The purpose of this article is to examine adhesive performance as a # function of operating temperature. This is the sixth in a series of # articles examining the proper use and the expected performance of # various commercially available adhesives, rims and tires. Unlike you, I have ridden tubulars almost exclusively for the last 30+ years. Oh? How do you know how many years I rode tubulars? I made no reference to how long you rode tubulars, I don't know how many years you rode them, and I don't care. What I *do* know is that you haven't ridden them with any regularity for about thirty years, and I know this because you have told us this over and over here on this NG. You seem to gloss over your words "Unlike you..." I am sure I have ridden at least as many tubulars in more conditions than you, judging from your claims. Besides, the articles in the above web site should mainly convince readers that they do not want to partake in these arcane and time consuming rituals. I sense that they are trying to say something useful while covering their liability, the latter being the main thrust. As I have mentioned, in the days when there were no useful racing clinchers, I held Wednesday evening tubular repair sessions for the local racers. The items in the FAQ on tubulars is all well tested. The stuff in the FAQ is dated. OH? Please let me know what isn't up to date? What has changes in tubulars other than that some of them have no stitching and others use adhesives that make them unrepairable. Sometimes I do, sometimes I don't. What I don't do is keep a bunch of extra tubulars lying around, and what I also don't do is pull off a glued tire to make it a spare and replace it with a new one. To be perfectly honest, I don't pre-glue *new* spares either, but I realize that I probably should. Sometimes I will put on a used (pre-glued) spare, buy a new tire and put it under the saddle, and ride around on the spare for a couple of weeks before I get around to gluing it down, if it is a rear tire. And then my decision about which tire to glue and which to keep as a spare will be based on different factors like which is the better tire and what are their relative conditions. So no, I don't follow a regimen. Somehow your scenario doesn't make sense. When you have a flat or two, you must patch them on the road and re-mount them if you don't have patched tubulars at home. Nonsense. I mount the spare, take the flat home and either repair it or not. Then the repaired tire, or a new replacement tire becomes the spare for the next ride. You only need three functional tires in this "regimen" unless you get two flats in one ride, which has only happened once that I remember, although I have a vague feeling that it may have happened another time in the distant past. I see you believe in the one-flat-per-ride theory... which is mainly theoretical. When riding alone we always carries two spares on any ride farther than we wanted to walk. Form years of experience, most riders have at least two tires as spares that resulted from a home repair while two other tires are on the bicycle. Since most riders have more than one set of wheels, there are at least two spares in reserve. I don't visualize how you handle this but it seems hypothetical. I have spare wheels; they don't have tires mounted on them. That hasn't really been a need since I last raced years ago. You mean... since I last rode actively... Racing has nothing to do with this. That's the whole point- "how much force" is what resists the damn tire rolling off. You seemed to think it important to some degree since in the FAQ you point out that inflation is what you think is the force keeping the tire on the rim. Well that isn't the point. Tires don't roll as you imagine. They are held in place by inflation constriction and kept from creeping significantly by the glue. Even with rim cement, they move. Inflation constriction certainly helps to keep them in place; that doesn't prove that it is the primary force holding them on the wheel when using the best contemporary glues. I think that if you took some demanding descents around here, you too would have to reverse your front wheel to make the tire creep back to where the stem is again radial from reverse creep. This is old hat and hasn't changed. Given that VM is a relatively new glue, and proven that at high rim temperatures is retains more strength than the old glues did at optimal temperatures, it is clear that it *has* changed. As long as it is a pressure sensitive glue it is also thermo plastic and will creep on hot braking descents. As I have described, I used thick cotton webbing soaked in epoxy as heat barriers on my rims to prevent this. Just the same, insulation has only so much resistance and in time heat comes through. I rode with heat barriers for many years and still have two sets of these wheels gathering dust. I can pull of a fully glued and inflated tire. So what? I'd be willing to wager that if I carefully glued a tire on with VM and pumped it up, you *couldn't* pull it off by hand, but, what the hell, I'm sure there are people out there stronger than me that could, and maybe you're one of them. I don't think you've tried. If the tire is changeable on the road when flat then it can be pushed off the rim with thumb pressure. I don't think you know with what your are disagreeing. The constriction force is correct and is valid for tubulars and clinchers with bias ply cords. Just slow down a bit and review what is being discussed. You're right; I didn't read it- no need to: if it says that constriction force acts to prevent a tubular from coming off the rim, I'm sure it's right; if it purports to prove that it is the only significant way that a tubular is held onto a rim, it is wrong, and I know it is wrong because I have personal experience comparing constriction force to VM glue as a way of holding the tire on the rim. There is no doubt: the VM bond is stronger. No calculation, however elegant, can be right if it does not describe reality. Stop creating straw men! In fact, your own testing years ago suggests that I may be right. Just consider the possibility that a road glue may have been developed that matches the bond strength of old track glue. If that has happened, and the above referenced tests indicate that it has, then everything that I have argued here follows from your own tests. As I said, you cannot match that with a pressure sensitive glue. You don't want to either, because the tire could not be changed in case of a flat. SO what is it that you don't believe? I don't believe you know what you are talking about. I don't believe you are capable of analyzing new data on this subject because you have too much emotional investment in your old experience with obsolete materials. I would like to hear some factual data that supports your view of tubular tire adhesion and replacement. It seems that you are only willing to say my perspective is all wrong and old fashioned. It is the tubular that is old fashioned. I wouldn't be calling someone an "old fart" if I were you. "Old fart" is a state of mind, not chronological years. Ain't *that* the truth. Like I said. aka "as I said". I take it English is a second language for you. 780 GRE verbal. No one says "as I said" in this context, especially not in a paragraph with the word "ain't". I think you know not of what you speak. You don't understand the difference between "like" and "as".
|
|
#37
June 3rd 05, 09:13 PM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
Dans le message de ,
a réfléchi, et puis a déclaré : Ain't *that* the truth. Like I said. aka "as I said". I take it English is a second language for you. 780 GRE verbal. No one says "as I said" in this context, especially not in a paragraph with the word "ain't". I think you know not of what you speak. You don't understand the difference between "like" and "as". Please stop trying to act as though you were exceptionally literate. Were English not only your first language (?), but had you also mastered it, I would not have read the innumerable errors in your text which I have excised, to spare others. Spell checking may help you, but a correctly spelled but inapt word is something you failed to correct several times in this exchange. I remember calling your attention once before to your inability to distinguish conversational (and transcribed) colloquial English from grammar book paradigms. Were the great authors of the language of Shakespeare not able to twist the "rules" to masterful effect, we would only have a lot of technical writers to read for pleasure. BTW, you seem not to have brought forward your extensive experience in rigorous testing and evaluating either tubular or clincher tires for the last two decades. I, for one, would enjoy being enlightened by the results you have obtained on the hundreds of both types of tires. I think that SocSec would no longer doubt the raw and assembled data himself. He could even rise to an admission, should we get to read your recnt research. -- Bonne route, Sandy Verneuil-sur-Seine FR PS : have you had the opportunity to digest the frame stiffness testing clippings I sent you ? I'd like your reaction to them, if you find time.
|
|
#38
June 3rd 05, 09:23 PM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
|
|
#39
June 3rd 05, 10:42 PM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
wrote:
someone sniped anonymously: So which is it? Have they or have they not changed "all that much"? Since I happen to think that the data supports the latter, I will grant you this: they may not be the best glues to use for a spare tire. That would match my experience that the contact cement method of gluing tires that you recommend does not create the strongest bond with VM. If they have then they won't stick again with a spare tire. I said, "the contact cement method of gluing tires that you recommend does not create the strongest bond with VM". I did *not* say that it will not create any bond. And I agree with you on something else: that inflation constriction provides a significant force to keep tires on tubular rims. Not the best, but adequate for my riding. I have stated before that I don't worry about it that much on a rear tire. You can't have it both ways. You're constructing a false dichotomy. Either it's a permanent one-use glue or it is a tacky one that accepts resuse for changing a tire. Or maybe something in between. The best glues were available 30 years ago just as they are today. No, they weren't. VM was not and I don't believe Conti was either. Glues for new uses have been developed since but for reusable rim glues, there has been no advance. You really have no idea, and absolutely no evidence to support this statement. You have pulled it out of thin air. I have noticed taking VM-glued tires off and only seeing the white glue, but I admit that doesn't mean anything. The real question is whether the degree of squirm is as great as with the old glues. Some squirm would produce some oxide; a quarter as much squirm might produce the same amount of oxide if the tire was used 4x as long- very, very difficult to draw any meaningful conclusions from the presence of aluminum oxide without a very carefully controlled test procedure. Oh BS! There wasn't a wheel that was ridden in the local mountains that didn't have significant creep on steep, hard braking descents. If your tires come off lily white I doubt that you demand much from your glue. OR, THEY DON'T SQUIRM THAT MUCH! (Or they weren't on that long before they had to be pulled off.) What happens to your spares when they are folded? Depends. Does the glue stick to itself and need to be pulled apart to open the tire for mounting? This whole picture doesn't make sense. I already told you that I use new tires for spares sometimes. I *don't* specifically pre-glue spares; I depend on "inflation constriction" and rim glue to get me home, and maybe old glue on the tire. http://www.engr.ku.edu/~ktl/bicycle/bicycle.html Selecting one of these items that harp on tire roll-off as if that were the big threat, I find the temperature one most revealing in its lack of field experience. Here again, tire roll-off is the thrust rather than the more serious one of linear creep that piles the tire up against the stem and causes a blowout. No mention of this is made, indicating that these folks don't descent hard or have any idea of the real hazard of tubulars that has plagues them for a long time. Force to roll off a tire is simply a way to measure bond strength. If the glue retains as much bond strength as other glues have when cold, it doesn't matter which direction the force is applied to measure bond strength. It will not be able to creep anymore than it will be able to roll off. Or, are you suggesting that these glues are directional in their strength, like some kind of carbon fiber glue? I think their testing is valid, and can be extrapolated to the conditions you are worried about. You certainly have no data to the contrary and I think your criticism is the last resort of a person who has nothing left of substance to stand on. In the days if yore, when many of the major Alpine passes were unpaved, descending with continuous braking was the norm and caused major tire creep. Beyond that, they talk of 70 degC when more than 100 degC is common. As I have related, steam hissing out of the stem hole in the rim alerted me to the higher temperatures caused by braking, after riding in snow for a longer distance. This is not the days of yore. Nevertheless, if their testing shows improved bonding at 70C it is probably still stronger than your old glues at 100C. But I will keep your advice in mind the next time I am descending unpaved Alpine roads and make sure that my bike is equipped with a disc brake. # TUBULAR TIRES: ADHESIVES AND PRACTICE # PART 6 # Adhesive Performance at Higher Temperatures # C. S. Chip (snipped background info) # Proper adhesive selection and proper # application are necessary to minimize the potential for roll-off. # Given the temperature rise due to braking during descents, the # subsequent lateral stress placed on the adhesive bonds in corners # and slides and the potential for serious injury to the rider, it is # important for the mechanic to know how the adhesive will perform. Exactly. So don't use your old glues, use VM. It is the only logical choice for someone who has found tire creep to be an issue in their descending. Unlike you, I have ridden tubulars almost exclusively for the last 30+ years. Oh? How do you know how many years I rode tubulars? I made no reference to how long you rode tubulars, I don't know how many years you rode them, and I don't care. What I *do* know is that you haven't ridden them with any regularity for about thirty years, and I know this because you have told us this over and over here on this NG. You seem to gloss over your words "Unlike you..." No, that was a comment on our relative experience with tubulars during the period in which these new glues were introduced. Your experience with the old glues is irrelevant. I am sure I have ridden at least as many tubulars in more conditions than you, judging from your claims. Irrelevant experience, because it is not contemporary. In fact, worse than irrelvant, because you think you are experienced, but your experience is obsolete. Besides, the articles in the above web site should mainly convince readers that they do not want to partake in these arcane and time consuming rituals. I sense that they are trying to say something useful while covering their liability, the latter being the main thrust. The papers appear to me to be academic in nature. OH? Please let me know what isn't up to date? A. The glues referenced. B. The gluing method. What has changes in tubulars other than that some of them have no stitching and others use adhesives that make them unrepairable. It's not the tires, it's the glues. I see you believe in the one-flat-per-ride theory... which is mainly theoretical. It's not a question of theory, it's one of probability. When riding alone we always carries two spares on any ride farther than we wanted to walk. For the once-every-fifteen-years probability, I will deal with it when it happens rather than try to strap on an extra tubular for that long shot (unless I win the lottery in which case I gotta figure something about my luck is changing). I have spare wheels; they don't have tires mounted on them. That hasn't really been a need since I last raced years ago. You mean... since I last rode actively... Racing has nothing to do with this. Hell, I rode 165 miles in the last week. And, of course racing has something to do with this- you train on different wheel/tire sets from those on which you race. Now there is no race, so no special wheelsets. Given that VM is a relatively new glue, and proven that at high rim temperatures is retains more strength than the old glues did at optimal temperatures, it is clear that it *has* changed. As long as it is a pressure sensitive glue it is also thermo plastic and will creep on hot braking descents. So all thermo plastic materials have the exact same temperature sensitivity and exhibit that plasticity at the same temperature? As I have described, I used thick cotton webbing soaked in epoxy as heat barriers on my rims to prevent this. Just the same, insulation has only so much resistance and in time heat comes through. I rode with heat barriers for many years and still have two sets of these wheels gathering dust. Gathering dust is probably a good use for them. I don't think you've tried. If the tire is changeable on the road when flat then it can be pushed off the rim with thumb pressure. As I have said before here, it is not really changeable on the road after a flat without some kind of tool to pry the tire off the rim, at least enough to get your hand under it. I have used I small allen wrench which a was able to work under the tire and then use it to pry up more of the tire. So, yes, I have tried. If I can get it off with my hands, I did not do a good job of gluing the tire. Stop creating straw men! You first! That story about tubular glue resisting the heat of braking on unpaved Alpine roads in the 60s is a strawman if I ever heard of one. I would like to hear some factual data that supports your view of tubular tire adhesion and replacement. The data is in the studies I referenced. It seems that you are only willing to say my perspective is all wrong and old fashioned. It is the tubular that is old fashioned. It apparently, nevertheless, still presents the best weight and rolling resistance available, despite your testing with Avocet. I think you know not of what you speak. You don't understand the difference between "like" and "as". I think you don't understand the difference between colloquial and "proper" English. Actually, no, I don't think that. I think that you're making this pointless criticism because you got nothin' else.
|
|
#40
June 4th 05, 07:07 AM
|
|||
|
|||
|
Cleaning Glue off of Tire Sidewalls?
In article
. com, wrote: wrote: someone sniped anonymously: So which is it? Have they or have they not changed "all that much"? Since I happen to think that the data supports the latter, I will grant you this: they may not be the best glues to use for a spare tire. That would match my experience that the contact cement method of gluing tires that you recommend does not create the strongest bond with VM. If they have then they won't stick again with a spare tire. I said, "the contact cement method of gluing tires that you recommend does not create the strongest bond with VM". I did *not* say that it will not create any bond. And I agree with you on something else: that inflation constriction provides a significant force to keep tires on tubular rims. Not the best, but adequate for my riding. I have stated before that I don't worry about it that much on a rear tire. You can't have it both ways. You're constructing a false dichotomy. Either it's a permanent one-use glue or it is a tacky one that accepts resuse for changing a tire. Or maybe something in between. The best glues were available 30 years ago just as they are today. No, they weren't. VM was not and I don't believe Conti was either. Glues for new uses have been developed since but for reusable rim glues, there has been no advance. You really have no idea, and absolutely no evidence to support this statement. You have pulled it out of thin air. I have noticed taking VM-glued tires off and only seeing the white glue, but I admit that doesn't mean anything. The real question is whether the degree of squirm is as great as with the old glues. Some squirm would produce some oxide; a quarter as much squirm might produce the same amount of oxide if the tire was used 4x as long- very, very difficult to draw any meaningful conclusions from the presence of aluminum oxide without a very carefully controlled test procedure. Oh BS! There wasn't a wheel that was ridden in the local mountains that didn't have significant creep on steep, hard braking descents. If your tires come off lily white I doubt that you demand much from your glue. OR, THEY DON'T SQUIRM THAT MUCH! (Or they weren't on that long before they had to be pulled off.) What happens to your spares when they are folded? Depends. Does the glue stick to itself and need to be pulled apart to open the tire for mounting? This whole picture doesn't make sense. I already told you that I use new tires for spares sometimes. I *don't* specifically pre-glue spares; I depend on "inflation constriction" and rim glue to get me home, and maybe old glue on the tire. http://www.engr.ku.edu/~ktl/bicycle/bicycle.html Selecting one of these items that harp on tire roll-off as if that were the big threat, I find the temperature one most revealing in its lack of field experience. Here again, tire roll-off is the thrust rather than the more serious one of linear creep that piles the tire up against the stem and causes a blowout. No mention of this is made, indicating that these folks don't descent hard or have any idea of the real hazard of tubulars that has plagues them for a long time. Force to roll off a tire is simply a way to measure bond strength. If the glue retains as much bond strength as other glues have when cold, it doesn't matter which direction the force is applied to measure bond strength. It will not be able to creep anymore than it will be able to roll off. Or, are you suggesting that these glues are directional in their strength, like some kind of carbon fiber glue? I think their testing is valid, and can be extrapolated to the conditions you are worried about. You certainly have no data to the contrary and I think your criticism is the last resort of a person who has nothing left of substance to stand on. In the days if yore, when many of the major Alpine passes were unpaved, descending with continuous braking was the norm and caused major tire creep. Beyond that, they talk of 70 degC when more than 100 degC is common. As I have related, steam hissing out of the stem hole in the rim alerted me to the higher temperatures caused by braking, after riding in snow for a longer distance. This is not the days of yore. Nevertheless, if their testing shows improved bonding at 70C it is probably still stronger than your old glues at 100C. But I will keep your advice in mind the next time I am descending unpaved Alpine roads and make sure that my bike is equipped with a disc brake. # TUBULAR TIRES: ADHESIVES AND PRACTICE # PART 6 # Adhesive Performance at Higher Temperatures # C. S. Chip (snipped background info) # Proper adhesive selection and proper # application are necessary to minimize the potential for roll-off. # Given the temperature rise due to braking during descents, the # subsequent lateral stress placed on the adhesive bonds in corners # and slides and the potential for serious injury to the rider, it is # important for the mechanic to know how the adhesive will perform. Exactly. So don't use your old glues, use VM. It is the only logical choice for someone who has found tire creep to be an issue in their descending. Unlike you, I have ridden tubulars almost exclusively for the last 30+ years. Oh? How do you know how many years I rode tubulars? I made no reference to how long you rode tubulars, I don't know how many years you rode them, and I don't care. What I *do* know is that you haven't ridden them with any regularity for about thirty years, and I know this because you have told us this over and over here on this NG. You seem to gloss over your words "Unlike you..." No, that was a comment on our relative experience with tubulars during the period in which these new glues were introduced. Your experience with the old glues is irrelevant. I am sure I have ridden at least as many tubulars in more conditions than you, judging from your claims. Irrelevant experience, because it is not contemporary. In fact, worse than irrelvant, because you think you are experienced, but your experience is obsolete. Besides, the articles in the above web site should mainly convince readers that they do not want to partake in these arcane and time consuming rituals. I sense that they are trying to say something useful while covering their liability, the latter being the main thrust. The papers appear to me to be academic in nature. You disparage a paper that _you_ cited. I copy the initial portion of the posted message that you used to cite the paper that you disparage. Path: newssvr14.news.prodigy.com!newsdbm04.news.prodigy. com!newsdst01.news.prodigy.c om!newsmst01b.news.prodigy.com!prodigy.com!newscon 02.news.prodigy.com!prodigy. net!news.glorb.com!postnews.google.com!z14g2000cwz .googlegroups.com!not-for-ma il From: Newsgroups: rec.bicycles.tech Subject: Cleaning Glue off of Tire Sidewalls? Date: 3 Jun 2005 10:36:28 -0700 Organization: http://groups.google.com Lines: 174 Message-ID: .com References: om . com .com .com NNTP-Posting-Host: 65.196.69.130 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1117820193 2806 127.0.0.1 (3 Jun 2005 17:36:33 GMT) X-Complaints-To: NNTP-Posting-Date: Fri, 3 Jun 2005 17:36:33 +0000 (UTC) In-Reply-To: User-Agent: G2/0.2 Complaints-To: Injection-Info: z14g2000cwz.googlegroups.com; posting-host=65.196.69.130; posting-account=strlcgwAAAD552heKSkZrQOKRJhU3dfJ Xref: newsmst01b.news.prodigy.com rec.bicycles.tech:577220 wrote: someone sniped anonymously: With Vittoria Mastik the rim can be heated to a point where you can't touch it and it still maintains more strength than the glues you used in your day do at their optimal operating temp. But even you admitted in a previous post that extreme braking conditions are required to heat rims to that degree, that usually wind resistance provides enough braking that the rim does not need to reach that temperature. You are fooling yourself if you believe that. Glues haven't changed all that much The strongest glues did not exist when you did your testing. and if they have they are on the border of not being useful for a spare tire if they are not soft enough when at room temperature to hold. So which is it? Have they or have they not changed "all that much"? Since I happen to think that the data supports the latter, I will grant you this: they may not be the best glues to use for a spare tire. That would match my experience that the contact cement method of gluing tires that you recommend does not create the strongest bond with VM. OK, so let's rephrase that: If you inspect your used rims, you will see that the glue is full of aluminum oxide, the grey color and that the base tape of the tire has eroded the aluminum rim. I have noticed taking VM-glued tires off and only seeing the white glue, but I admit that doesn't mean anything. The real question is whether the degree of squirm is as great as with the old glues. Some squirm would produce some oxide; a quarter as much squirm might produce the same amount of oxide if the tire was used 4x as long- very, very difficult to draw any meaningful conclusions from the presence of aluminum oxide without a very carefully controlled test procedure. They are not "Brown's comments' and the glues mentioned are similar to other favorite brands. Not according to recent testing. Those glues don't come close to Conti or especially VM in strength. This is the same old story we've been hearing every year throughout the days when people still rode tubulars. It's only how much you believe the ad copy. I don't read ad copy, I don't buy cycling mags. Does anyone actually advertise tubular glues? I am basing my "story" on the testing shown at: http://www.engr.ku.edu/~ktl/bicycle/bicycle.html -- Michael Press
|
| Thread Tools | |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Easy Coker Airfoil tire change | john_childs | Unicycling | 27 | June 21st 05 01:52 AM |
| getting a tubular off the rim quickly | peet9471 | Techniques | 15 | December 23rd 04 10:19 PM |
| When to change the tire | Jose Capco | Techniques | 10 | July 1st 04 08:15 PM |
| DIY Tire Removal 2 | g.daniels | Techniques | 4 | May 21st 04 05:25 PM |
| DIY Tire Remval 2 | g.daniels | Techniques | 1 | May 17th 04 10:26 PM |
Linear Mode
