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Trailer Tires Overheating.
This past Summer, took our 15 foot fiberglass on a long road trip
instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? |
Trailer Tires Overheating.
Joe,
Doubt it would have helped. Matter of fact if the temps of the tires were high enough it would have encouraged evaporation thus increasing pressure considerably. Furthermore, the water would never have contacted the rim during travel as centrifugal force would hold the water against the tread area, right? Of course, the smaller the tire the more rotations it makes for a given speed. I have learned to always use the largest diameter wheels/tires possible on trailers. For a small trailer it could require an axle upgrade but would be worth it, IMO. BTW, I'd pull those hubs and take a real close look at the wheel bearings. They probably got pretty warm on that drive??? Butch Joe wrote: This past Summer, took our 15 foot fiberglass on a long road trip instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? |
Trailer Tires Overheating.
On Sat, 25 Oct 2003 09:39:29 -0400, Joe Here wrote:
This past Summer, took our 15 foot fiberglass on a long road trip instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? I agree with Butch, plus I think you would have been courting disaster for this reason: At higher speeds, the water might well have concentrated in a single area in the wheel. This makes the wheel unbalanced and out-of-round. As the wheel goes out of round, the effect is magnified. A blow-out might well have occurred. As Butch said - use larger tires. Also, if you don't already have them, bearing buddies are a very big help in keeping the bearings lubricated, particularly when you use the bra to keep water out. -- Larry email is rapp at lmr dot com |
Trailer Tires Overheating.
This past Summer, took our 15 foot fiberglass on a long road trip
instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? nitrogen helps tires run cooler |
Trailer Tires Overheating.
"Wwj2110" wrote in message nitrogen helps tires run cooler How does that work? JG |
Trailer Tires Overheating.
As some one else said check the wheel bearings. Also raise the air pressure to
the max allowable for the tires ( usually imprinted on the side wall ). NEVER NEVER PUT WATER IN HIWAY TIRES. The centrifugal force could tear the tire apart or worse in my opinion the water could get hot engulf to turn to steam and blow up. Mike *********** This past Summer, took our 15 foot fiberglass on a long road trip instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? |
Trailer Tires Overheating.
They have it at race tracks. Otherwise you need a tank of it. Know anyone
in the hvac business, they use it to purge refrigerant lines while they braze. Not really likely to help enouhg to be worth the trouble though. The other posters are right, bigger wheels are the right solution. "John Gaquin" wrote in message ... "Wwj2110" wrote in message nitrogen helps tires run cooler How does that work? JG |
Trailer Tires Overheating.
I don't think they run cooler, but I know that using nitrogen the pressure
stays more consistant as the tire heat up "John Gaquin" wrote in message ... "Wwj2110" wrote in message nitrogen helps tires run cooler How does that work? JG |
Trailer Tires Overheating.
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Trailer Tires Overheating.
Interesting. I wonder if this was to provide more mass to absorb the
overpressure aspect of the blast (should the mine be detonated). Anyone know about this stuff? I the army, (S.A.D.F.) we used to put water in our Unimog tires. This was for land mines & I'm not sure exactly why. They were however capable of near highway speeds. |
Trailer Tires Overheating.
Kevin Anderson wrote:
I don't think they run cooler, but I know that using nitrogen the pressure stays more consistant as the tire heat up Do you guys stay up late making this stuff up or do you really, honestly believe that? Have you ever heard of - much less read - the "gas laws'? Look up a French chap named Charles and Gay-Lussac and their particular contribution to the art. Exactly how do you "know that using nitrogen the pressure stays more consistant (sic) as the tire heats up"? The reason nitrogen is used in high performance tires (usually aircraft) is that it will not support combustion or oxidation of rubber compounds in a very high temperature application. Compressed nitrogen is normally dry, very low in moisture content as well as completely free of oil which is a contaminant delivered by many air compressors. All the normal gas laws still apply. The only thing worse than the general lack of basic scientific knowledge shown here is the willingness of people to post that they "know" that the laws of physics simply don't apply. Rick |
Trailer Tires Overheating.
"Rick" wrote in message ink.net... Kevin Anderson wrote: I don't think they run cooler, but I know that using nitrogen the pressure stays more consistant as the tire heat up Do you guys stay up late making this stuff up or do you really, honestly believe that? Have you ever heard of - much less read - the "gas laws'? Look up a French chap named Charles and Gay-Lussac and their particular contribution to the art. Exactly how do you "know that using nitrogen the pressure stays more consistant (sic) as the tire heats up"? The reason nitrogen is used in high performance tires (usually aircraft) is that it will not support combustion or oxidation of rubber compounds in a very high temperature application. Compressed nitrogen is normally dry, very low in moisture content as well as completely free of oil which is a contaminant delivered by many air compressors. All the normal gas laws still apply. The only thing worse than the general lack of basic scientific knowledge shown here is the willingness of people to post that they "know" that the laws of physics simply don't apply. Rick Um, Rick, Race car operators take a great deal of time and effort to first dry their tires, then fill them with dry nitrogen. The reason is that the water in the air does NOT act like an ideal gas. Think about what happens to the pressure/volume curves as the tire reaches 100 degrees C. http://www.porschenet.com/bruns04.html There are other perceived benefits that may induce an operator to switch to nitrogen. I am not ready to support this other stuff, but throw it in just to cover the subject more fully. http://www.branick.com/n2/faq.html Mark Browne |
Trailer Tires Overheating.
Mark Browne wrote:
Um, Rick, Race car operators take a great deal of time and effort to first dry their tires, then fill them with dry nitrogen. The reason is that the water in the air does NOT act like an ideal gas. yeah, and did you notice that I wrote: Compressed nitrogen is normally dry, very low in moisture content ... Rick |
Trailer Tires Overheating.
"Rick" wrote in message ink.net... Mark Browne wrote: Um, Rick, Race car operators take a great deal of time and effort to first dry their tires, then fill them with dry nitrogen. The reason is that the water in the air does NOT act like an ideal gas. yeah, and did you notice that I wrote: Compressed nitrogen is normally dry, very low in moisture content ... Rick Yes, but now the others on this group have a better understanding of the factors involved. Mark Browne |
Trailer Tires Overheating.
Mark Browne wrote:
Yes, but now the others on this group have a better understanding of the factors involved. I am not going to bother to run the numbers but the partial pressure of any "normal" quantity of water vapor in a tire is not going to change the tire pressure by an amount easily measured by anyone outside a laboratory. It will have no significant influence. Moisture will however contribute to corrosion and oxidation at elevated temperatures in an oxygen bearing atmosphere. How much of a factor this is in an application where tires are changed every few minutes anyway is debatable. I think your racer/writer/engineer friend might be disappointed when he fails to see much, if any, measurable difference in his tire pressure. Rick |
Trailer Tires Overheating.
Joe Here wrote in message . ..
This past Summer, took our 15 foot fiberglass on a long road trip instead in the usual half mile to the marina. The tires are the small 4.80-8 utiltiy type tires, and needless to say, they overheated badly..... long story, but I'll be upgrading to a biger tire this Summer. Here's my question. It seemed that the speed at which the load was being carried created the heat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. I never did this, but have pondered the the effects of water in a tire at speed. Would the balance go for a bundle or would the water be thrown evenly within the tire by the certifugal force? I made the trip home by upping the pressure to 60 p.s.i. and by driving slower. Would water have helped of would I have been courting a disaster? No, water would have just added to the mass. I have a boat with 8" tires. I had 4.80-8's on it, told the guy at the tire shop that I thought they got too hot, he put on 5.70-8's on, problem solved. You can use the same wheels. They stay MUCH cooler. If you look, after mounting one and blowing it up, and compare it to the 4.80, you'll see a difference in heighth as well as width. It doesn't make as many turns per mile as the smaller tire! The load range is greater, the recommended tire pressure greater, and the contact patch greater. Trust me, been there, done that. |
Trailer Tires Overheating.
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Trailer Tires Overheating.
basskisser wrote:
nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. You really ought to stop kissing fish, it has diminished your powers of reason. rick |
Trailer Tires Overheating.
"Mark Browne" wrote in message news:8H_mb.39146 The reason is that the water in the air does NOT act like an ideal gas. Gosh, I didn't realize that there had been a change in the laws of physics since I went to college! When did this happen? Man, things were easier back in my day when any gas obeyed the gas laws! Remember when the steam tables were what you would use for any gas you didn't know the properties of? Think about what happens to the pressure/volume curves as the tire reaches 100 degrees C. The vapor pressure for water will vary over a very large temperature range. Fortunately, it is predicatable and monotonic. If you didn't have liquid water in the tires when they were cold, you won't have any liquid in them as they heat up. I can see reasons that a race car might want to use nitrogen in their tires. It is a nice, safe gas. It is realatively cheap. The fact that it is readily available in a very dry state can have its advantages: I can imagin that avoiding any condesation when the tire was cold could be an issue, especially during the winter. The issue would be maintaining a "predictable" inflation pressure as the tires went from "colder than when they were inflated" to nominal operating temperatures. I suppose that condensation could also be an issue when the wheels were balanced. Rod |
Trailer Tires Overheating.
"Joe Here" wrote in message ... Here's my question. It seemed that the speed at which the load was being carried created the heat. It is the flexing of the sidewalls that creates most of the heat. The more they flex, and the faster they flex, the more heat is generated. A taller tire rotates slower, thus a given spot will flex less often, thus it won't get as hot. A stiffer tire won't flex as much. A tire with a higher load rating will be stiffer. Tires are stiffer when properly inflated. Thus, a tire that is not overloaded and is properly inflated shouldn't overheat. While pondering the trip home (semi desperate and after a few beers) I considered filling the tires with water (say 50%) in an attempt to dissipate the heat to the rims. As others have said, NO! If nothing else, this will cause a major imbalance in the tire. Rod |
Trailer Tires Overheating.
Rick wrote in message link.net...
basskisser wrote: nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. You really ought to stop kissing fish, it has diminished your powers of reason. rick Well, then, please explain to the world how in the HELL nitrogen will make a tire run cooler. You apparently don't know squat about the Laws of Gases. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. Do you refute that? If so, do tell why. Now, I suspect that you don't UNDERSTAND my answer, and that is the reason that you don't think it's correct. So, allow me to explain. The nitrogen doesn't expand as much as air, for a given temperature change. Therefore, the nitrogen doesn't increase tire pressure as much as air, when the temperature starts increasing. Thus, a tire is less likely to expand, because of temperature increase, to the point of rupture. BUT, the nitrogen does NOTHING to keep the temperature of the tire from increasing, or decreasing for that matter. |
Trailer Tires Overheating.
basskisser wrote:
basskisser wrote: nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. Rick wrote: You really ought to stop kissing fish, it has diminished your powers of reason. Basskisser whined: Well, then, please explain to the world how in the HELL nitrogen will make a tire run cooler. It doesn't. The tire heats the gas by conduction and radiation as it flexes. The gas doesn't heat the tire. Only reducing tire flexure will make the tire run cooler. It doesn't matter one single molecule what the gas filler is. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. Do you refute that? Yes, along with many generations of scientifically literate people, I do refute that bonehead statement. Nitrogen follows the gas laws just as every other gas. Your interpretation of natural phenomena and physics will not change the gas laws for one gas in one application. The nitrogen doesn't expand as much as air, for a given temperature change. Therefore, the nitrogen doesn't increase tire pressure as much as air, when the temperature starts increasing. Please refer to the gas laws. You cannot rewrite them as much as you would like to believe you have. BUT, the nitrogen does NOTHING to keep the temperature of the tire from increasing, or decreasing for that matter. Well done, you are beginning to get it. However: You started this by writing: nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. Try and keep your story consistent. That statement reads that nitrogen keeps tires cool because it doesn't expand like air. Both statements are false. You may believe the gas laws are suspended for automotive applications but do try at least to keep track of your misapprehensions. I think most of this nonsense about nitrogen in tires not expanding as much as air comes from the fact that few people really understand the properties of gases. There is a little phrase in the gas laws that refers to "phase change" ... that is where the followers of the myth may be running aground - (boating content). Liquid nitrogen will vaporize to produce a volume of gas that occupies about 700 times that of the liquid. Liquid oxygen will vaporize to produce a gas that occupies around 860 times the volume. Vaporization is the phase change. Once the liquid has evaporated the resultant gas, nitrogen, oxygen, or water vapor, will follow the gas laws and when the correct law is applied (there are several) the properties of those gases are very predictable and if you understood them you would see that the properties of those gases are identical in their behavior under the conditions which race car teams and trailer boaters operate. Rick |
Trailer Tires Overheating.
"basskisser" wrote in message om... . You apparently don't know squat about the Laws of Gases. Can you please state which law you are referring to? I am familiar with Boyles Law, and Charles Law, the "ideal gas" law. I am not aware of any gas law that supports your claims. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. More linear? The basic ideal gas law is PV=nRT. P = pressure V = volume n = the number of moles (a measure of the number of atoms) R is a constant (8.3144 exp-7) T = temperature in absolute units ("room temperature" is ~300 K) How do you get more linear than that? Do you refute that? Yes If so, do tell why. It is generally accepted that all gases obey the ideal gas law if you stay away from their condensation temperature. Air is mostly nitrogen, then oxygen, carbon dioxide, and traces of many other gases including water. Unless you have artificially introduced liquid water into the tire, or inflated the tire with air super saturated with moisture, the typical operating temperature of the tire will sufficienty above the dew point of the air inside such that the air (complete with water vapor) will obey the ideal gas law. The nitrogen doesn't expand as much as air, for a given temperature change. Which gas are you saying doesn't obey the gas laws: air or nitrogen? What temperature and pressure are you making this claim for? Rod |
Trailer Tires Overheating.
On Tue, 28 Oct 2003 13:37:32 -0800, "Rod McInnis"
wrote: "basskisser" wrote in message . com... . You apparently don't know squat about the Laws of Gases. Can you please state which law you are referring to? I am familiar with Boyles Law, and Charles Law, the "ideal gas" law. I am not aware of any gas law that supports your claims. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. More linear? The basic ideal gas law is PV=nRT. P = pressure V = volume n = the number of moles (a measure of the number of atoms) R is a constant (8.3144 exp-7) T = temperature in absolute units ("room temperature" is ~300 K) How do you get more linear than that? Do you refute that? Yes [...] This is just too funny watching basskisser get himself all wrapped up in another boneheaded scientific argument. Every time he types something he confirms he doesn't understand the world around him. I can't wait to see how he tries to weasel out of this one without admitting he's wrong. Stay tuned. Steve |
Trailer Tires Overheating.
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Trailer Tires Overheating.
"Rod McInnis" wrote in message
It is generally accepted that all gases obey the ideal gas law if you stay away from their condensation temperature. Not true. Unless you introduce nitrogen to the tire under ideal conditions, which would entail a vacuum process first. Do you really think that people are going to do that, when all they need is a larger tire? Air is mostly nitrogen, then oxygen, carbon dioxide, and traces of many other gases including water. Bingo, you're starting to get it. Water. Unless you have artificially introduced liquid water into the tire, or inflated the tire with air super saturated with moisture, the typical operating temperature of the tire will sufficienty above the dew point of the air inside such that the air (complete with water vapor) will obey the ideal gas law. Again, unless introduced under ideal conditions, there WILL be water vapor. The nitrogen doesn't expand as much as air, for a given temperature change. Which gas are you saying doesn't obey the gas laws: air or nitrogen? Niether. What temperature and pressure are you making this claim for? Operating range of the tire. |
Trailer Tires Overheating.
Rick you are a ****i## college educated idiot all in Christ world that was
asked was a method to keep the tires cooler nitrogen will period. You get on here and act like an ass! If I could get to you there are some physics lessons I like to show you. Ron K "Rick" wrote in message ink.net... basskisser wrote: basskisser wrote: nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. Rick wrote: You really ought to stop kissing fish, it has diminished your powers of reason. Basskisser whined: Well, then, please explain to the world how in the HELL nitrogen will make a tire run cooler. It doesn't. The tire heats the gas by conduction and radiation as it flexes. The gas doesn't heat the tire. Only reducing tire flexure will make the tire run cooler. It doesn't matter one single molecule what the gas filler is. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. Do you refute that? Yes, along with many generations of scientifically literate people, I do refute that bonehead statement. Nitrogen follows the gas laws just as every other gas. Your interpretation of natural phenomena and physics will not change the gas laws for one gas in one application. The nitrogen doesn't expand as much as air, for a given temperature change. Therefore, the nitrogen doesn't increase tire pressure as much as air, when the temperature starts increasing. Please refer to the gas laws. You cannot rewrite them as much as you would like to believe you have. BUT, the nitrogen does NOTHING to keep the temperature of the tire from increasing, or decreasing for that matter. Well done, you are beginning to get it. However: You started this by writing: nitrogen helps tires run cooler Only because when nitrogen is used instead of air, the pressure to temperature ratio is more linear. Try and keep your story consistent. That statement reads that nitrogen keeps tires cool because it doesn't expand like air. Both statements are false. You may believe the gas laws are suspended for automotive applications but do try at least to keep track of your misapprehensions. I think most of this nonsense about nitrogen in tires not expanding as much as air comes from the fact that few people really understand the properties of gases. There is a little phrase in the gas laws that refers to "phase change" ... that is where the followers of the myth may be running aground - (boating content). Liquid nitrogen will vaporize to produce a volume of gas that occupies about 700 times that of the liquid. Liquid oxygen will vaporize to produce a gas that occupies around 860 times the volume. Vaporization is the phase change. Once the liquid has evaporated the resultant gas, nitrogen, oxygen, or water vapor, will follow the gas laws and when the correct law is applied (there are several) the properties of those gases are very predictable and if you understood them you would see that the properties of those gases are identical in their behavior under the conditions which race car teams and trailer boaters operate. Rick |
Trailer Tires Overheating.
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Trailer Tires Overheating.
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Trailer Tires Overheating.
"Rick" wrote in message ink.net... Mark Browne wrote: Yes, but now the others on this group have a better understanding of the factors involved. I am not going to bother to run the numbers but the partial pressure of any "normal" quantity of water vapor in a tire is not going to change the tire pressure by an amount easily measured by anyone outside a laboratory. It will have no significant influence. Moisture will however contribute to corrosion and oxidation at elevated temperatures in an oxygen bearing atmosphere. How much of a factor this is in an application where tires are changed every few minutes anyway is debatable. I think your racer/writer/engineer friend might be disappointed when he fails to see much, if any, measurable difference in his tire pressure. Rick Rick, I believe that what you are neatly trying to side-step in your consideration is the presence of liquid water. If all we were talking about is water vapor, even at 100% humidity, then I would completely agree that you are right. Unfortunately there *can* be liquid water trapped inside the tire. Some of this comes from tire mounting compound, some from air compressors without suitable dryers, some from water inside the tire. This trapped water inside the tire can be standing on the surface, or inside the rubber. It is rather difficult to make a blanket statement about how much effect each source can contribute. This makes an unassailable mathematical analysis equally difficult. Not to worry - others have done it and I have read the reports. In a Formula or NASCAR setting moisture can raise tire pressure about 4 PSI in the corners. This is enough to mess up a finely tuned race car chassis. Whatever *it* is, either it works, or it does not. If *it* does not make cars go faster or safer, most people don't put a lot of time and money into it. Real race teams that have real physicists and engineers on their staff go to considerable effort to control the presence of water inside the tire. Tire moisture *is* a significant problem in racing; people worry about going into a corner at 200 miles an hour and having their car go squirrelly in the middle of the turn. I spend a fair amount of time working around race tracks and see a lot of people shoot their mouths off about how things *should* work. The nice thing about racing is that most of this stuff gets sorted out on the track. If you would like to field a car and fill the tires with normal air to prove that there is no difference, by all means go ahead. The nice thing about racing is that people that know what they are talking about go fast, and clueless people watch 'em go by. It all gets sorted out when the rubber hits the road! Mark Browne |
Trailer Tires Overheating.
Mark Browne wrote:
I believe that what you are neatly trying to side-step in your consideration is the presence of liquid water. If all we were talking about is water vapor, even at 100% humidity, then I would completely agree that you are right. Unfortunately there *can* be liquid water trapped inside the tire. Some of this comes from tire mounting compound, some from air compressors without suitable dryers, some from water inside the tire. This trapped water inside the tire can be standing on the surface, or inside the rubber. Wasn't this discussion about using nitrogen in the tires? If the racers are so particular why are they using wet air from a cheap air compressor and still worry about the effects of moisture? Why are they using practices and processes that are known to add worrisome quantities of liquid water to a component that is so sensitive to moisture? Which way do you guys want this? Perfectly predictable tire pressures will be impossible to obtain when the mounting is done with shade tree techniques as you describe. If there is so much water in a tire despite the best efforts of "real physicists and engineers on their staff (who)go to considerable effort to control the presence of water inside the tire" then something is missing in this equation. In a Formula or NASCAR setting moisture can raise tire pressure about 4 PSI in the corners. I find this a bit hard to believe. If it is water vapor it will respond exactly like the nitrogen or air and the pressure rise is due to the temperature increase of the tire. That is one of the gas laws that no one seems to want to follow. If there is liquid water in the tire a whole new set of conditions exist that are still unlikely to produce the effect you describe. Look at it another way. If you can attribute that 4 psi increase to moisture then why not control the amount of moisture in the tire ... dry the tire and add a measured amount of water so that you can predict the pressure increase and regulate accordingly? But if you can dry the tire then why worry about moisture? If you cannot dry the tire then you can measure the dew point of the filling gas and calculate the weight of the water in the tire and predict accordingly. It sounds to me like you guys are just using "rules of thumb" and are surprised when you get surprised. What is the normal tire pressure on one of those cars? Thirty - forty psig? Let's say the tire started out at 35 psi, for the water to boil away and increase the pressure of the tire to 39 psi its temperature would have to increase to somewhere around 285 degrees F. Do you run your tires at those temperatures? For the tires to increase 4 psi in the second or two of cornering due to boiling water the carcass temperature of the tire would have to be damn near glowing since heat does not transfer instantaneously to the water, nor does it cool instantaneously as the car leaves the corner. If the starting temperature and pressure of the tire in the pits was 35 psig at 80 degrees F and it heated up to 200 degrees in the corner its pressure would raise to around 46 psig ... at that pressure any water would still be water until it reached over 290 degrees ... I have not even mentioned the fact that the heat to vaporize the water comes from the tire and the other gases filling the tire. The transfer of that heat actually cools the tire and the gas ... a minute amount, yes, but the effect of water has to be an equally minute amount and I have yet to be shown the mechanism whereby "normal" amounts of water in a tire will produce the effect you describe in the conditions in which tires operate. If you can explain how race car tires somehow work differently than other machines I would love to hear it. I am very open minded but this smacks of voodoo engineering to me. Rick |
Trailer Tires Overheating.
"basskisser" wrote in message om... Again, unless introduced under ideal conditions, there WILL be water vapor. Key word "vapor". It obeys the ideal gas law as long as you stay away from the condesation points. If you had inflated the tire from an air compressor that included a storage tank then the air had originally been at a much higher pressure. The higher pressure increases the "dew point" considerably which usually results in water condensing in the tank of the air compressor. A high quality air compressor will provide for an automatic water drain, cheaper units simply provide a drain valve at the bottom. Either way, the air that travels down the air hose ends up drier than the air that was originally pumped into the tank. Assuming that you aren't pumping your trailer tires up to a couple hundred PSI, the air in the tires will be significantly less than the air in the storage tank was. At the lower pressure, the dew point will be significantly higher, making it much less likely that you will condense any of the vapor back into liquid. You could create a sceanario where you could end up with enough water vapor pumped into the tire so that at some realistic temperature there would be enough condensation to create a measurable change in pressure. If a fraction of a PSI matters that much to you then it would be trivial to avoid such a sceanario at far less cost than dealing with nitrogen. Which gas are you saying doesn't obey the gas laws: air or nitrogen? Niether. This is an interesting statement. Are you saying that the ideal gas laws are wrong, or that for some reason nitrogen is not an ideal gas? Do you think there are no ideal gases at all? The condensation point for nitrogen at any reasonable pressure is damn cold! The rubber on the tire will get hard and brittle long before you got anywhere close to the condensation point of nitrogen! Your understanding of thermodynamics is simply wrong! Do a web search on "ideal gas" or "PV=nRT" or "boyles law". There are plenty of sites from major universities that will educate you on this. Rod |
Trailer Tires Overheating.
"Rod McInnis" wrote in message ...
"basskisser" wrote in message om... Again, unless introduced under ideal conditions, there WILL be water vapor. Key word "vapor". It obeys the ideal gas law as long as you stay away from the condesation points. If you had inflated the tire from an air compressor that included a storage tank then the air had originally been at a much higher pressure. The higher pressure increases the "dew point" considerably which usually results in water condensing in the tank of the air compressor. A high quality air compressor will provide for an automatic water drain, cheaper units simply provide a drain valve at the bottom. Either way, the air that travels down the air hose ends up drier than the air that was originally pumped into the tank. Assuming that you aren't pumping your trailer tires up to a couple hundred PSI, the air in the tires will be significantly less than the air in the storage tank was. At the lower pressure, the dew point will be significantly higher, making it much less likely that you will condense any of the vapor back into liquid. You could create a sceanario where you could end up with enough water vapor pumped into the tire so that at some realistic temperature there would be enough condensation to create a measurable change in pressure. If a fraction of a PSI matters that much to you then it would be trivial to avoid such a sceanario at far less cost than dealing with nitrogen. Which gas are you saying doesn't obey the gas laws: air or nitrogen? Niether. This is an interesting statement. Are you saying that the ideal gas laws are wrong, or that for some reason nitrogen is not an ideal gas? Do you think there are no ideal gases at all? Nope, never said either. And I never said that either air, or nitrogen "doesn't obey the gas laws." The condensation point for nitrogen at any reasonable pressure is damn cold! The rubber on the tire will get hard and brittle long before you got anywhere close to the condensation point of nitrogen! That has absolutely nothing to do with the fact that that nitrogen doesn't expand at the same rate as oxygen for any given temperature change. Do you deny this? Your understanding of thermodynamics is simply wrong! Do a web search on "ideal gas" or "PV=nRT" or "boyles law". There are plenty of sites from major universities that will educate you on this. Rod No, it's not. You simply don't understand my position. |
Trailer Tires Overheating.
(Steven Shelikoff) wrote in message ...
On 29 Oct 2003 04:27:31 -0800, (basskisser) wrote: Please refute my statements, or shut up. Quit stalking me. lol. Stalking you? I didn't even respond to you. You're so stupid you can't even follow a thread. Steve Idiot. If you aren't stalking me, why did you bother to refer to me in a response that had NOTHING to do with the topic? |
Trailer Tires Overheating.
snip That has absolutely nothing to do with the fact that that nitrogen doesn't expand at the same rate as oxygen for any given temperature change. Do you deny this? snip Now you have my curiosity! I understand all gases to expand about 1/270 per degree C at room temperature. Please explain how now nitrogen and oxygen differ? Mark Browne |
Trailer Tires Overheating.
Mark Browne wrote:
Now you have my curiosity! I understand all gases to expand about 1/270 per degree C at room temperature. Please explain how now nitrogen and oxygen differ? This should be a good one ... but don't hold your breath waiting for a response. I am just amazed that he doesn't just look up the gas laws and see for himself. Bizarre. Bass posted this and I haven't heard from him since I answered him, so if you attempt to explain it to him maybe he will finally just go away. You apparently don't know squat about the Laws of Gases. Now, Im again telling you that the ONLY reason is that the pressure to temperature ratio is more linear. Do you refute that? If so, do tell why. Now, I suspect that you don't UNDERSTAND my answer, and that is the reason that you don't think it's correct. So, allow me to explain. The nitrogen doesn't expand as much as air, for a given temperature change. The level of scientific illiteracy in this country is frightening when you see it defended so hotly by those with the smallest armory. Rick |
Trailer Tires Overheating.
"Mark Browne" wrote in message news:qv8ob.62616$Tr4.167581@attbi_s03... snip That has absolutely nothing to do with the fact that that nitrogen doesn't expand at the same rate as oxygen for any given temperature change. Do you deny this? snip Now you have my curiosity! I understand all gases to expand about 1/270 per degree C at room temperature. Please explain how now nitrogen and oxygen differ? Mark Browne Nitrogen has an atomic weight of 14 and oxygen is 16? I can live on pure oxygen, but pure nitrogen will kill me? By the way, is is more like 1/300 at room temperature unless you live in a very cold room.... :-) PV=nRT or PV=NkT del cecchi |
Trailer Tires Overheating.
"basskisser" wrote in message om... That has absolutely nothing to do with the fact that that nitrogen doesn't expand at the same rate as oxygen for any given temperature change. Do you deny this? Yes. I deny this. Mr. Boyle denies this. Mr. Charles denies this. Mr. Gay and Mr. Lussac deny this. They wrote laws of physics about it. Every chemistry, physics and thermodynamics class uses these laws. Here, don't take my word for it, let's take a look at some of the information available from the net. As an example: Department of Chemistry California State University, Sacramento http://kekule.chem.csus.edu/gaslaws Boyle's Law Simply stated, Boyle's Law indicates that for a fixed amount of gas (fixed number of moles) at a fixed temperature, the pressure and the volume are inversely proportional. pV = constant or p1V1 = p2V2 In other words, as the pressure increases, the volume decreases. (When you squeeze on a balloon to increase the pressure, the volume of the balloon goes down.) Charles' Law Simply stated, Charles' Law indicates that for a fixed amount of gas (fixed number of moles) at a fixed pressure, the volume is proportional to the temperature. V/T = constant or V1/T1 = V2/T2 In other words, as the temperature increases, the volume increases. (When you heat a balloon the volume of the balloon goes up.) Gay-Lussac's Law Simply stated, Gay-Lussac's Law indicates that for a fixed amount of gas (fixed number of moles) at a fixed volume, the pressure is proportional to the temperature. p/T = constant or p1/T1 = p2/T2 In other words, as the temperature increases, the pressure increases. (When you put a pickle jar in the refridgerator, the drop in pressure from the trapped air becoming colder makes it hard to open the jar later!) Note that there is no factor in these equations for the type of gas. If you take a rigid container that contains a gas, any gas and heat it up the pressure will increase a known and predictable amount. You double the temperature, you double the pressure. These three laws combine together to create the "ideal gas" law, whihc is PV=nRT. This law relates Pressure, Volume and Temperature. Give me the starting values, how much you changed the other two variable and I can tell you exactly what the third variable will be. I don't need to know what the gases are involved. The only time that you deviate from the ideal gas law is if you reach a pressure/temperature point where the gas might change state into a liquid. You had some basis for an argument with water at room temperatures, but oxygen and nitrogen are not ever going to be liquid at any pressure you are likely to have in your tires. Air will obey the ideal gas law as long as it isn't saturated with water vapor, and as I pointed out earlier you would have to try hard to get saturated air into the tires. Rod |
Trailer Tires Overheating.
Rod McInnis wrote:
Mr. Gay and Mr. Lussac deny this. I don't know what those two guys contributed to the gas laws but maybe they were related to Joseph Gay-Lussac and helped out with his balloons or something. 8-) Rick |
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