Presta vs Schrader Valves
03-06-20, 09:13 AM
#76
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Can you recommend a source for just the valve head? I'd be interested in finding Presta screw on heads for my shop air compressor and for my trail Morph pumps.
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03-06-20, 09:24 AM
#77
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Carbon dioxide is actually the heaviest of all the naturally occurring atmospheric gases. It's also a huge molecule in terms of the bond lengths. Oxygen, nitrogen and water are all fairly small in comparison. The issue with it diffusing out of rubber isn't the size but the way it interacts with the rubber. Oxygen, nitrogen and water vapor...in order of rapidity...diffuse through the rubber via small channels and holes in the rubber and are rather slow to do it. Water can't really get out of the rubber at all because of it's molecular shape and the electron configuration.
Carbon dioxide, on the other hand, doesn't just diffuse through the rubber, it actually dissolves through the rubber. It doesn't weaken the rubber but it makes a kind of solid/gas solution and zips right through. It has a lot to do with the electron configuration and the shape of the CO2 molecule.
All of the gases with the exception of water (which really isn't a "gas") will diffuse from the high pressure system in the tire to the lower pressure outside the tire. CO2 just does it better than the other gases.
Carbon dioxide, on the other hand, doesn't just diffuse through the rubber, it actually dissolves through the rubber. It doesn't weaken the rubber but it makes a kind of solid/gas solution and zips right through. It has a lot to do with the electron configuration and the shape of the CO2 molecule.
All of the gases with the exception of water (which really isn't a "gas") will diffuse from the high pressure system in the tire to the lower pressure outside the tire. CO2 just does it better than the other gases.
03-06-20, 09:29 AM
#78
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Thread Starter
It sounds like you have a pump chuck like this one.
The issue you seem to be having is that you are jamming the head on to the Presta valve as far as it will go. You don't need to do that. All you need to do is to clear the threads for the valve cap and throw the thumb lock. The valve shouldn't come in contact with anything inside the chuck. It doesn't need to and it's detrimental to keeping air in the tube. Let the valve work like it is supposed to...as a check valve. No need to hold it open.
The problem with the Lezyne (and many other pump chuck designs) is that it sacrifices the simplicity of the Presta valve for no reason. The Lezyne head needs to be screwed into place. It's fiddly. "Smart heads" (which aren't, really), have a soft pin that pushes on the Presta valve which is also not needed. The Silca chuck simply slips on and slips off. There's nothing inside the head that even touches the pin on the Presta valve. Slide it on and pump the tire. Slide it off when done.
The Silca is a bit expensive...$40!!!!...but there are others that work just as well without costing an arm, leg and first born child. The SKS adapter
is usually less than $10 and works as well as the Silca without the name.
Generally, a 16 oz cartridge is enough of only one tire and maybe a little bit...depends on the volume and pressure of the tire. If there is any left over, it will probably leak out before you can use it again. The seals on the head aren't all that good.
Carbon dioxide is actually the heaviest of all the naturally occurring atmospheric gases. It's also a huge molecule in terms of the bond lengths. Oxygen, nitrogen and water are all fairly small in comparison. The issue with it diffusing out of rubber isn't the size but the way it interacts with the rubber. Oxygen, nitrogen and water vapor...in order of rapidity...diffuse through the rubber via small channels and holes in the rubber and are rather slow to do it. Water can't really get out of the rubber at all because of it's molecular shape and the electron configuration.
Carbon dioxide, on the other hand, doesn't just diffuse through the rubber, it actually dissolves through the rubber. It doesn't weaken the rubber but it makes a kind of solid/gas solution and zips right through. It has a lot to do with the electron configuration and the shape of the CO2 molecule.
All of the gases with the exception of water (which really isn't a "gas") will diffuse from the high pressure system in the tire to the lower pressure outside the tire. CO2 just does it better than the other gases.
The issue you seem to be having is that you are jamming the head on to the Presta valve as far as it will go. You don't need to do that. All you need to do is to clear the threads for the valve cap and throw the thumb lock. The valve shouldn't come in contact with anything inside the chuck. It doesn't need to and it's detrimental to keeping air in the tube. Let the valve work like it is supposed to...as a check valve. No need to hold it open.
The problem with the Lezyne (and many other pump chuck designs) is that it sacrifices the simplicity of the Presta valve for no reason. The Lezyne head needs to be screwed into place. It's fiddly. "Smart heads" (which aren't, really), have a soft pin that pushes on the Presta valve which is also not needed. The Silca chuck simply slips on and slips off. There's nothing inside the head that even touches the pin on the Presta valve. Slide it on and pump the tire. Slide it off when done.
The Silca is a bit expensive...$40!!!!...but there are others that work just as well without costing an arm, leg and first born child. The SKS adapter
is usually less than $10 and works as well as the Silca without the name.
Generally, a 16 oz cartridge is enough of only one tire and maybe a little bit...depends on the volume and pressure of the tire. If there is any left over, it will probably leak out before you can use it again. The seals on the head aren't all that good.
Carbon dioxide is actually the heaviest of all the naturally occurring atmospheric gases. It's also a huge molecule in terms of the bond lengths. Oxygen, nitrogen and water are all fairly small in comparison. The issue with it diffusing out of rubber isn't the size but the way it interacts with the rubber. Oxygen, nitrogen and water vapor...in order of rapidity...diffuse through the rubber via small channels and holes in the rubber and are rather slow to do it. Water can't really get out of the rubber at all because of it's molecular shape and the electron configuration.
Carbon dioxide, on the other hand, doesn't just diffuse through the rubber, it actually dissolves through the rubber. It doesn't weaken the rubber but it makes a kind of solid/gas solution and zips right through. It has a lot to do with the electron configuration and the shape of the CO2 molecule.
All of the gases with the exception of water (which really isn't a "gas") will diffuse from the high pressure system in the tire to the lower pressure outside the tire. CO2 just does it better than the other gases.
What you said is exactly what I am doing. I am looking at that little thin PrestI Valve and remember the trouble I had getting a seal with a cheap pump I once had and I jam the pump head onto the valve with my thumb and air blows past my thumb. I am pushing down too far and opening the check valve. It is a unique design of the PrestI Valve with the check valve that the Schrader does not have that prevents air from escaping if you have a leaky head or pump hose. I can see that feature and I can see there are better heads like the Silka and less expensive but just as functional SKS that are designed right to work with the PrestI slipping it on creating its own seal without screwing something on or engaging a hard to engage lever. That would make using PrestI much easier. I get that. My objection with PrestI Valves is its narrow,weak base where it attaches to the tube. The Schrader's is much,much better and the valve locks into the rim hole better and is more compact. They are not as chic but I think they are more reliable and foolproof. I base everything on reliability, it is crucial to me,crucial. So I do not need a more efficient PrestI system because I do not like them and am not going to use them. So the Lezyne Head really looks good to me for using it on Schrader Valves. It really looks like a good tool and surprisingly reasonably priced for such a nice looking tool. They also have a small, carry pump reasonably priced which I assume is of equal quality that is reasonably priced for such a nice tool.You are going to carry a pump over Co2 every time over reliability to handle any situation?
I assumed Co2 dissipated rather quickly because it is a lighter gas. It is not,it is a heavier gas. It dissipates because of a molecular reaction. I did not know any of this. It is basically a one time, short term use. I should have kept the package. Maybe I will carry both cartridges to get some use out of them. Another thing, after each flat you have to buy another cartridge. You will pay for a Lizyne pump in no time.
Last edited by mjac; 03-06-20 at 09:37 AM.
03-06-20, 10:00 AM
#79
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Try Presto valves. They work like magic.
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03-06-20, 10:00 AM
#80
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A couple of things were going on here. One,I do not know this person. I have never corresponded with them. I have no idea what their level of experience is. I wanted to know if they had tubular tires and tubeless tires mixed up so I could answer correctly. How was I supposed to know they knew what sew ons were. Not everyone does. I was trying to clarify that.Two, not knowing this person and them not knowing me they call me a Troll and insult my intelligence.That is not going to fly.
Ironically, I completely agreed with their original post and believe it was accurate in the reason PrestI Valves continued to be used after sew ons even to today. That and people being able to continue to use their pumps after clinchers were introduced.
Ironically, I completely agreed with their original post and believe it was accurate in the reason PrestI Valves continued to be used after sew ons even to today. That and people being able to continue to use their pumps after clinchers were introduced.
Last edited by mjac; 03-06-20 at 10:47 AM.
03-06-20, 10:36 AM
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So at what point did we stop using Woods valves and what was wrong with them? Having a threaded hose that screws on seems to be back in style so maybe we should go back to Woods. They seemed to be quite good at not leaking any air out when you were attaching and removing the hose.
03-06-20, 10:48 AM
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It's hard to say. Helium goes through latex quickly and probably through a butyl rubber tube slower because of the increased thickness. But it's likely caused by straight diffusion based on size of the molecule. Helium is a noble gas and doesn't interact with the world all that well. I'd suspect the same for Argon. Diffusion is a function of molecular size for the most part but CO2 is special because of it's interaction with the rubber.
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03-06-20, 11:01 AM
#83
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Thread Starter
So at what point did we stop using Woods valves and what was wrong with them? Having a threaded hose that screws on seems to be back in style so maybe we should go back to Woods. They seemed to be quite good at not leaking any air out when you were attaching and removing the hose.
03-06-20, 11:04 AM
#84
Senior Member
Thread Starter
It's hard to say. Helium goes through latex quickly and probably through a butyl rubber tube slower because of the increased thickness. But it's likely caused by straight diffusion based on size of the molecule. Helium is a noble gas and doesn't interact with the world all that well. I'd suspect the same for Argon. Diffusion is a function of molecular size for the most part but CO2 is special because of it's interaction with the rubber.
03-06-20, 11:17 AM
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It's one of the better "improved" head designs as long as you remember to push the lever to the opposite side that you have attached to the valve.
Yep. Pushing it down too far. Don't bury the valve as deep and it will work just fine.
The Schrader has it's own weaknesses and isn't nearly as foolproof as you make it out to be. Schraders are prone to cutting the rubber sheath on the valve stem. That makes them just as delicate as the Presta. For some reason, Presta valves don't creep as much as Schraders seem to. Seldom do I see a Presta valve canted in the valve hole. I often see Schrader valves that are at an odd angle in the valve hole. Often those Schrader valves are showing signs of being cut or are cut. It's still pretty delicate.
In my experience, Schrader valves also suffer more problems if you use sealant. The spring mechanism clogs rather easily. I don't use sealant with any regularity but I see a lot of clogged valves at my local co-op. Almost 100% of them are Schrader. This may be due to more tubes with sealant being Schrader tubes in the past but I really haven't seen that many Presta valves that have been clogged with their greater use now in tubeless setups. There's less in the valve to clog.
Presta valves are chic, they are just simple. Lots of people appreciate that simplicity. YMMV
Most of us do the same. I haven't found Presta valves to be unreliable. I have 11 bikes in my garage currently. Every one has a Presta valve in each tire. I also have a trailer that has a Presta valve in it (it's difficult to find 20" Presta tubes). I've also been using Presta valves on my bikes for decades in every possible condition and never had a systemic problem using them. I've used them on multi-week tours throughout the US and they have been overwhelmingly reliable. I've had a few valves separate from the tube but I've also experienced valve stem cuts when I used Schraders in the distant past. In both situations, I blame the uses...me...not the tube.
As for the Lezyne head, I find the same problem with the Schrader side as I do with the Presta side. Screwing on the head is bothersome and time consuming. On the Schrader side, because of the pin opening the valve, there's even more opportunities for leakage on the Schrader side. The head on a Topeak Morph, for example, makes a better seal for both kinds of valve. Yes, the head has to be disassembled to change from one head to the other but most people use one kind of tube so it's not a major issue.
What you said is exactly what I am doing. I am looking at that little thin PrestI Valve and remember the trouble I had getting a seal with a cheap pump I once had and I jam the pump head onto the valve with my thumb and air blows past my thumb. I am pushing down too far and opening the check valve.
In my experience, Schrader valves also suffer more problems if you use sealant. The spring mechanism clogs rather easily. I don't use sealant with any regularity but I see a lot of clogged valves at my local co-op. Almost 100% of them are Schrader. This may be due to more tubes with sealant being Schrader tubes in the past but I really haven't seen that many Presta valves that have been clogged with their greater use now in tubeless setups. There's less in the valve to clog.
Presta valves are chic, they are just simple. Lots of people appreciate that simplicity. YMMV
I base everything on reliability, it is crucial to me,crucial. So I do not need a more efficient PrestI system because I do not like them and am not going to use them. So the Lezyne Head really looks good to me for using it on Schrader Valves. It really looks like a good tool and surprisingly reasonably priced for such a nice looking tool. They also have a small, carry pump reasonably priced which I assume is of equal quality that is reasonably priced for such a nice tool.You are going to carry a pump over Co2 every time over reliability to handle any situation?
As for the Lezyne head, I find the same problem with the Schrader side as I do with the Presta side. Screwing on the head is bothersome and time consuming. On the Schrader side, because of the pin opening the valve, there's even more opportunities for leakage on the Schrader side. The head on a Topeak Morph, for example, makes a better seal for both kinds of valve. Yes, the head has to be disassembled to change from one head to the other but most people use one kind of tube so it's not a major issue.
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03-06-20, 11:19 AM
#87
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Nope. Science.
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03-06-20, 11:24 AM
#88
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So at what point did we stop using Woods valves and what was wrong with them? Having a threaded hose that screws on seems to be back in style so maybe we should go back to Woods. They seemed to be quite good at not leaking any air out when you were attaching and removing the hose.
On a curious side note, long ago, we used to get a little rubber tube in some Rema Tip Top patch kits. I never knew what it was for until I saw a Dunlop valve.
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Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
03-06-20, 11:25 AM
#89
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Thread Starter
It's hard to say. Helium goes through latex quickly and probably through a butyl rubber tube slower because of the increased thickness. But it's likely caused by straight diffusion based on size of the molecule. Helium is a noble gas and doesn't interact with the world all that well. I'd suspect the same for Argon. Diffusion is a function of molecular size for the most part but CO2 is special because of it's interaction with the rubber.
03-06-20, 11:26 AM
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Does that actually matter though?
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
03-06-20, 11:34 AM
#92
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Thread Starter
Does that actually matter though?
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
03-06-20, 11:49 AM
#94
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And the cognoscenti all got it.
LOL, the tyro troll exposes his naivete again in comic manner.
The question wasn't about SEW-UPS, it was about your ability to engage in conversation about bicycle mechanics.
Look @mjac - This issue has been discussed in this forum hundreds of times; you're not interested in the answer, you're interested in arguing. We're all helpful people in here, but we have limited patience with newbs who don't know their stuff and tell us we're all wrong.
The question wasn't about SEW-UPS, it was about your ability to engage in conversation about bicycle mechanics.
Look @mjac - This issue has been discussed in this forum hundreds of times; you're not interested in the answer, you're interested in arguing. We're all helpful people in here, but we have limited patience with newbs who don't know their stuff and tell us we're all wrong.
Last edited by DiabloScott; 03-06-20 at 12:11 PM.
03-06-20, 11:53 AM
#95
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Does that actually matter though?
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
I certainly try to avoid it, but I saw a picture where someone had carved all the rubber off to force the then essentially bare metal stem of a schrader tube into a presta rim.
I guess it would depend on if the rubber sheath over the metal has any role in the ultimate rubber to metal seal.
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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!
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!
03-06-20, 12:01 PM
#96
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Thread Starter
It's one of the better "improved" head designs as long as you remember to push the lever to the opposite side that you have attached to the valve.
Yep. Pushing it down too far. Don't bury the valve as deep and it will work just fine.
The Schrader has it's own weaknesses and isn't nearly as foolproof as you make it out to be. Schraders are prone to cutting the rubber sheath on the valve stem. That makes them just as delicate as the Presta. For some reason, Presta valves don't creep as much as Schraders seem to. Seldom do I see a Presta valve canted in the valve hole. I often see Schrader valves that are at an odd angle in the valve hole. Often those Schrader valves are showing signs of being cut or are cut. It's still pretty delicate.
In my experience, Schrader valves also suffer more problems if you use sealant. The spring mechanism clogs rather easily. I don't use sealant with any regularity but I see a lot of clogged valves at my local co-op. Almost 100% of them are Schrader. This may be due to more tubes with sealant being Schrader tubes in the past but I really haven't seen that many Presta valves that have been clogged with their greater use now in tubeless setups. There's less in the valve to clog.
Presta valves are chic, they are just simple. Lots of people appreciate that simplicity. YMMV
Most of us do the same. I haven't found Presta valves to be unreliable. I have 11 bikes in my garage currently. Every one has a Presta valve in each tire. I also have a trailer that has a Presta valve in it (it's difficult to find 20" Presta tubes). I've also been using Presta valves on my bikes for decades in every possible condition and never had a systemic problem using them. I've used them on multi-week tours throughout the US and they have been overwhelmingly reliable. I've had a few valves separate from the tube but I've also experienced valve stem cuts when I used Schraders in the distant past. In both situations, I blame the uses...me...not the tube.
As for the Lezyne head, I find the same problem with the Schrader side as I do with the Presta side. Screwing on the head is bothersome and time consuming. On the Schrader side, because of the pin opening the valve, there's even more opportunities for leakage on the Schrader side. The head on a Topeak Morph, for example, makes a better seal for both kinds of valve. Yes, the head has to be disassembled to change from one head to the other but most people use one kind of tube so it's not a major issue.
Yep. Pushing it down too far. Don't bury the valve as deep and it will work just fine.
The Schrader has it's own weaknesses and isn't nearly as foolproof as you make it out to be. Schraders are prone to cutting the rubber sheath on the valve stem. That makes them just as delicate as the Presta. For some reason, Presta valves don't creep as much as Schraders seem to. Seldom do I see a Presta valve canted in the valve hole. I often see Schrader valves that are at an odd angle in the valve hole. Often those Schrader valves are showing signs of being cut or are cut. It's still pretty delicate.
In my experience, Schrader valves also suffer more problems if you use sealant. The spring mechanism clogs rather easily. I don't use sealant with any regularity but I see a lot of clogged valves at my local co-op. Almost 100% of them are Schrader. This may be due to more tubes with sealant being Schrader tubes in the past but I really haven't seen that many Presta valves that have been clogged with their greater use now in tubeless setups. There's less in the valve to clog.
Presta valves are chic, they are just simple. Lots of people appreciate that simplicity. YMMV
Most of us do the same. I haven't found Presta valves to be unreliable. I have 11 bikes in my garage currently. Every one has a Presta valve in each tire. I also have a trailer that has a Presta valve in it (it's difficult to find 20" Presta tubes). I've also been using Presta valves on my bikes for decades in every possible condition and never had a systemic problem using them. I've used them on multi-week tours throughout the US and they have been overwhelmingly reliable. I've had a few valves separate from the tube but I've also experienced valve stem cuts when I used Schraders in the distant past. In both situations, I blame the uses...me...not the tube.
As for the Lezyne head, I find the same problem with the Schrader side as I do with the Presta side. Screwing on the head is bothersome and time consuming. On the Schrader side, because of the pin opening the valve, there's even more opportunities for leakage on the Schrader side. The head on a Topeak Morph, for example, makes a better seal for both kinds of valve. Yes, the head has to be disassembled to change from one head to the other but most people use one kind of tube so it's not a major issue.
I have to to disagree with you on the bases of the two valves. Just on an external inspection, the Sshrader's base is more sturdy and stable. My experience has been PrestI Valves split at their base. This might not be typical for other people, but it is for me. There is more room for error with the Schrader. I did not know about the Sealent issue, that is something to consider. I believe the chanting of Schrader stems is due to under inflation which people do chronically.
03-06-20, 12:03 PM
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
03-06-20, 12:08 PM
#98
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I am am curious about one thing, this is how I learn things.nWhy do you use a small hand pump, albeit with a Lenzne head to pump up a tire to 115-120 psi when they have compact Co2 systems that will do it in seconds. I do not understand this from a size perspective and a pumping perspective.
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
03-06-20, 12:10 PM
#99
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But this presents an opportunity. Get out your dril and drill the PrestI hole out and join the legions of no nonsense Schrader users. It would be good practice using the drill. That's what I ended up doing after another frustrating PrestI episode. It was liberating.
03-06-20, 12:20 PM
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Every rubber coated Schrader valve that I've seen cut has resulted in an unrepairable leak...just like a Presta detaching from the tube. What you may be seeing is a fully threaded Schrader valve.
What I have heard of people doing is drilling an additional presta-sized hole and reinforcing the rim tape in the area of the unused factory schrader one.
Last edited by UniChris; 03-06-20 at 12:25 PM.