More tubeless stuff
08-20-22, 02:25 PM
#1
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Thread Starter
More tubeless stuff
Okay so I recently finally had a tire failure with tubeless after quite a bit of use in terrain where I'd have had dozens or scores of flats. The sidewall was leaking where it was snakebit by the rim. I had been running very low pressure, probably lower than prudent. The tire was leaking slow enough that I could fill it and ride home, but given that it was pretty much worn out any way I decided to replace it without further efforts.
I decided to go ahead and replace both tires with Kenda Kozmik Lite II Pros. Strangely when replacing the old tires I found the rear one had clear amber liquid where there should have been milk white Stans sealant. The front one had the normal looking liquid, but was almost dry. Both had been tooped up this season. The only thing I know of that I did differently with the rear one was use CO2 to inflate it. So I checked and apparently CO2 GREATLY reduces the life of the sealant. This was only for a couple days and it completely killed the sealant, So beware of using CO2 with sealant! They don't get along well at least for Stans and probably others. That may be common knowledge, but I didn't know and so maybe others don't either so I figured a mention was in order.
I know most of us don't use CO2 on tour any way, but I did around home and found it to be a bad idea with Stan's and probably most other sealants. So just in case anyone wasn't aware, be advised that it is a problem.
I decided to go ahead and replace both tires with Kenda Kozmik Lite II Pros. Strangely when replacing the old tires I found the rear one had clear amber liquid where there should have been milk white Stans sealant. The front one had the normal looking liquid, but was almost dry. Both had been tooped up this season. The only thing I know of that I did differently with the rear one was use CO2 to inflate it. So I checked and apparently CO2 GREATLY reduces the life of the sealant. This was only for a couple days and it completely killed the sealant, So beware of using CO2 with sealant! They don't get along well at least for Stans and probably others. That may be common knowledge, but I didn't know and so maybe others don't either so I figured a mention was in order.
I know most of us don't use CO2 on tour any way, but I did around home and found it to be a bad idea with Stan's and probably most other sealants. So just in case anyone wasn't aware, be advised that it is a problem.
Last edited by staehpj1; 08-20-22 at 02:36 PM.
08-20-22, 07:15 PM
#2
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08-21-22, 05:14 AM
#3
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Yeah, I had no idea and was shocked when I popped the tire off and saw clear amber liquid with all the solids gone, apparently solidified in/on the inside of the tire after only a few days of CO2 exposure.
08-23-22, 11:14 AM
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Putting on my chemistry hat, I find any kind of reaction between carbon dioxide and tire sealant to be highly improbable. CO2 is very stable and it takes some very aggressive conditions as well as aggressive chemical to make it react. What you are seeing is probably more physical than chemical.
My first thought is that the CO2 as it was introduced was cold and reduced the temperature of the sealant too much. That’s a bit of a stretch because sealant is made of chemicals that have a fairly low freezing point. CO2 is cold when introduced but probably not that cold.
Another thought is the interaction of CO2, the glycols in the sealant, and the tires. Carbon dioxide is known to diffuse out of tires quickly. This is due to it dissolving in the rubber which other gases don’t do. The glycol in tire sealant also dissolves in the rubber which is why it “dries” out of a mostly liquid proof container. Combined, the CO2 and glycol may flow out of the tire faster than either one alone. The net effect of this increased removal could make the latex precipitate as the liquid glycol keeping it in suspension is reduced in volume.
My first thought is that the CO2 as it was introduced was cold and reduced the temperature of the sealant too much. That’s a bit of a stretch because sealant is made of chemicals that have a fairly low freezing point. CO2 is cold when introduced but probably not that cold.
Another thought is the interaction of CO2, the glycols in the sealant, and the tires. Carbon dioxide is known to diffuse out of tires quickly. This is due to it dissolving in the rubber which other gases don’t do. The glycol in tire sealant also dissolves in the rubber which is why it “dries” out of a mostly liquid proof container. Combined, the CO2 and glycol may flow out of the tire faster than either one alone. The net effect of this increased removal could make the latex precipitate as the liquid glycol keeping it in suspension is reduced in volume.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
08-23-22, 02:08 PM
#5
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Putting on my chemistry hat, I find any kind of reaction between carbon dioxide and tire sealant to be highly improbable. CO2 is very stable and it takes some very aggressive conditions as well as aggressive chemical to make it react. What you are seeing is probably more physical than chemical.
My first thought is that the CO2 as it was introduced was cold and reduced the temperature of the sealant too much. That’s a bit of a stretch because sealant is made of chemicals that have a fairly low freezing point. CO2 is cold when introduced but probably not that cold.
Another thought is the interaction of CO2, the glycols in the sealant, and the tires. Carbon dioxide is known to diffuse out of tires quickly. This is due to it dissolving in the rubber which other gases don’t do. The glycol in tire sealant also dissolves in the rubber which is why it “dries” out of a mostly liquid proof container. Combined, the CO2 and glycol may flow out of the tire faster than either one alone. The net effect of this increased removal could make the latex precipitate as the liquid glycol keeping it in suspension is reduced in volume.
My first thought is that the CO2 as it was introduced was cold and reduced the temperature of the sealant too much. That’s a bit of a stretch because sealant is made of chemicals that have a fairly low freezing point. CO2 is cold when introduced but probably not that cold.
Another thought is the interaction of CO2, the glycols in the sealant, and the tires. Carbon dioxide is known to diffuse out of tires quickly. This is due to it dissolving in the rubber which other gases don’t do. The glycol in tire sealant also dissolves in the rubber which is why it “dries” out of a mostly liquid proof container. Combined, the CO2 and glycol may flow out of the tire faster than either one alone. The net effect of this increased removal could make the latex precipitate as the liquid glycol keeping it in suspension is reduced in volume.
The chemistry is over my head, but I do know that CO2 permeates through tires pretty fast despite being a largeish molecule.
I do know that whatever happened it precipitated out all of the latex (or ebough to make the liquid transparent) by the time I removed the tired a couple days later. I guess there is a remote possibility there is some other factor that I am unaware of, but I doubt it.
08-23-22, 02:34 PM
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Without knowing the quantity or active ingredients of the sealant, I can only speculate. So here goes:
It wouldn't take much CO2 to saturate the sealant liquid, which would make it fairly acidic (pH <4 in an aqueous solution). That might be enough either to catalyze polymerization of the sealant. Alternatively, the H2CO3 (carbonic acid) in solution might react to precipitate out whatever is supposed to plug any leaks as carbonate.
But as I say, it's all speculation. Who's buying the beer, and pass me another piece of pizza!
It wouldn't take much CO2 to saturate the sealant liquid, which would make it fairly acidic (pH <4 in an aqueous solution). That might be enough either to catalyze polymerization of the sealant. Alternatively, the H2CO3 (carbonic acid) in solution might react to precipitate out whatever is supposed to plug any leaks as carbonate.
But as I say, it's all speculation. Who's buying the beer, and pass me another piece of pizza!
