New tyres, mmmmmm not too happy

[Phill D]

I'm not sure on this theory that oxygen passes through the tyre at a greater rate than nitrogen. Sounds like bunkum to me but I stand ready to be corrected.

As air is 78% nitrogen and that's what we all put in our tyres I question is there really significant benefit other than for very specialised applications for have 100%

 

[Ivory55]

Must admit it does sound a bit like the emperors new clothes to me

 

[gerry mcg]

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?
The correct answer, with respect to “permeation”, is yes.
Graham’s Law Explained: The Difference between Effusion and Permeation

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen.

We felt it best to leave it to the expertise of Dr. Keith Murphy to elaborate on the scientific principles:

https://www.getnitrogen.org/pdf/graham.pdf

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

 

[tonyidle]

Helium, yes, Nitrogen less so, but do you really want four potential fire bombs on your motorhome, well five if you have a spare as well.
Mike

?

 

[Gizmouk]

?

Just smile and nod

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[Phill D]

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?
The correct answer, with respect to “permeation”, is yes.
Graham’s Law Explained: The Difference between Effusion and Permeation

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen.

We felt it best to leave it to the expertise of Dr. Keith Murphy to elaborate on the scientific principles:

https://www.getnitrogen.org/pdf/graham.pdf

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

I have no doubt that is absolutely true. I just question that there is a real benefit over normal air inflation on a motorhome.

 

[gerry mcg]

I have no doubt that is absolutely true. I just question that there is a real benefit over normal air inflation on a motorhome.

I agree

 

[Redders69]

I have just had the same tyres fitted at my local tyre fitter. They got them direct from Continental and mine are week 42 2021.

 

[coroner]

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?
The correct answer, with respect to “permeation”, is yes.
Graham’s Law Explained: The Difference between Effusion and Permeation

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen.

We felt it best to leave it to the expertise of Dr. Keith Murphy to elaborate on the scientific principles:

https://www.getnitrogen.org/pdf/graham.pdf

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

Its free in costco to use nitrogen filling of new
tyres so might as well anyway

 

[BouncyBoatFolk]

Just smile and nod

Ah, I see what's happened there. So the thread initially was about tyres, and then became conflated [ not inflated ]with some of the supposed slight benefit's of filling tyres with nitrogen. Helium was also mentioned,possibly I assumed as an alternative. Helium, has a very small molecule which can migrate quite quickly through tyre walls, so not very good.
Unfortunately I confused Helium's properties [ inert ] with Hydrogen, [ very volatile , R101, Hindenburg ect.]Confusing the gasses properties I wrongly advised that using Helium might be a bad idea, which it is, but not for the reason I gave, there crystal clear.
Mike.

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[autorouter]

My tyres start with 78% nitrogen. If oxygen permeates out through the tyre walls faster than nitrogen, then they will very gradually deflate. What's left inside will be a higher concentration of nitrogen. If I top up with 78% nitrogen, then after several top-ups the tyres will contain getting on for 100% nitrogen.

 

[gpat]

Ah, I see what's happened there. So the thread initially was about tyres, and then became conflated [ not inflated ]with some of the supposed slight benefit's of filling tyres with nitrogen. Helium was also mentioned,possibly I assumed as an alternative. Helium, has a very small molecule which can migrate quite quickly through tyre walls, so not very good.
Unfortunately I confused Helium's properties [ inert ] with Hydrogen, [ very volatile , R101, Hindenburg ect.]Confusing the gasses properties I wrongly advised that using Helium might be a bad idea, which it is, but not for the reason I gave, there crystal clear.
Mike.

Helium has the considerable advantage that you could do the squeaky voice trick at MF rallies.

 

[gpat]

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?
The correct answer, with respect to “permeation”, is yes.
Graham’s Law Explained: The Difference between Effusion and Permeation

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen.

We felt it best to leave it to the expertise of Dr. Keith Murphy to elaborate on the scientific principles:

https://www.getnitrogen.org/pdf/graham.pdf

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

I stand corrected

 

[Rozzer]

Nitrogen generators have been around for many years and several big fleet operators haulage/ councils/ bus companies etc use them. The HGV generators cost several thousand pounds. They work by filtering out all the other gasses in the air to generate nitrogen. I have a “wand” costing about £100 bought a good few years ago. It works well. I check the O2 content with an oximeter occasionally and it still eliminates all O2. You won’t get 100% inside the tyre of course as you won’t be able to get all of the air out so it’s maybe 90%. I fill my youngsters tyres with it as they don’t check their tyre pressures often enough and N keeps them at the same pressure for many months. I don’t think they are a worthwhile investment for a family car as the oxidisation degradation factor isn’t relevant given the life of a tyre if you are doing say 10-15k per year. On a vehicle that does relatively few miles a year say a classic car or dare I say a Motorhome it does make sense.
The science is proven, not a marketing gag, Google tyre nitrogen generators if you want to check it out. Anyway - works for me - just saying

 

[gerry mcg]

Nitrogen generators have been around for many years and several big fleet operators haulage/ councils/ bus companies etc use them. The HGV generators cost several thousand pounds. They work by filtering out all the other gasses in the air to generate nitrogen. I have a “wand” costing about £100 bought a good few years ago. It works well. I check the O2 content with an oximeter occasionally and it still eliminates all O2. You won’t get 100% inside the tyre of course as you won’t be able to get all of the air out so it’s maybe 90%. I fill my youngsters tyres with it as they don’t check their tyre pressures often enough and N keeps them at the same pressure for many months. I don’t think they are a worthwhile investment for a family car as the oxidisation degradation factor isn’t relevant given the life of a tyre if you are doing say 10-15k per year. On a vehicle that does relatively few miles a year say a classic car or dare I say a Motorhome it does make sense.
The science is proven, not a marketing gag, Google tyre nitrogen generators if you want to check it out. Anyway - works for me - just saying

I guess they operate by reverse osmosis in a similar fashion to medical oxygen concentrators.u

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[Reallyretired]

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?
The correct answer, with respect to “permeation”, is yes.
Graham’s Law Explained: The Difference between Effusion and Permeation

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen.

We felt it best to leave it to the expertise of Dr. Keith Murphy to elaborate on the scientific principles:

https://www.getnitrogen.org/pdf/graham.pdf

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

If this is correct the air in your tyres will gradually become higher in nitrogen as the oxygen leaks out. By the time you've topped up the pressures a few times they will contain almost pure nitrogen at no cost.

 

[Sandancers]

.

 

[autorouter]

I guess they operate by reverse osmosis in a similar fashion to medical oxygen concentrators.

They are similar to oxygen concentrators, but it's not reverse osmosis. There's two chambers. Air in one chamber has the nitrogen absorbed in a complex compound like a sponge, and the oxygen plus the rest is left. When the sponge is full, the air is switched to the second chamber to repeat the process. Meanwhile in the first chamber, the nitrogen is removed from the 'sponge', either by heating or depressurisation, and the sponge is then empty again. The entire process takes about twenty minutes.

In an oxygen concentrator the oxygen is used, and nitrogen is the waste product. Obviously in a nitrogen generator it's the other way round.

 

[gpat]

If this is correct the air in your tyres will gradually become higher in nitrogen as the oxygen leaks out. By the time you've topped up the pressures a few times they will contain almost pure nitrogen at no cost.

It's certainly a credible theory.

 

[Spriddler]

I wrongly advised that using Helium might be a bad idea,

Helium would enable you to have a bit more payload.

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[Phill D]

Helium would enable you to have a bit more payload.

only if you filled the van with it...

 

[Augusta08]

We put Nitrogen in the race car because it doesn't expand as much when heated. With plain old air the tyres start at 14psi are 30psi after 6 laps. With Nitrogen we can start at 22psi and hit our target 30psi after 6 laps. Makes the car much more stable in thoose crucial first few laps.

 

[autorouter]

We put Nitrogen in the race car because it doesn't expand as much when heated. With plain old air the tyres start at 14psi are 30psi after 6 laps. With Nitrogen we can start at 22psi and hit our target 30psi after 6 laps. Makes the car much more stable in thoose crucial first few laps

The theory says that there should be very little difference in the expansion when heated between most common gases, including nitrogen, oxygen, air and CO2. This theory has been repeatedly confirmed by experiments with metal cylinders, pistons etc. I'd be interested in the explanation for the effect you describe. I don't think any water vapour content would make such a big difference.

 

[Augusta08]

The theory says that there should be very little difference in the expansion when heated between most common gases, including nitrogen, oxygen, air and CO2. This theory has been repeatedly confirmed by experiments with metal cylinders, pistons etc. I'd be interested in the explanation for the effect you describe. I don't think any water vapour content would make such a big difference.

It's the moisture thing, the RH in plain air is highly variable, Nitrogen does not support moisture. We like to get the tyres hot (makes them grip better) so we aim for an even temperature across the breadth of the tyre. Using a hand-held IR pyrometer aiming for 180-200F. We use Dunlop DZ03G 265x35x18's they come in at around £250 each, obviously anything we can do to stabilise pressures is done.

 

[johnandi]

Going back to the orginal topic in the thread. I phoned our insurers (Comfort) to ask about whether they put any lifespans on tyres as ours are 6yrs old. I asked mechanic to check condition of ours on recent MOT, including cracks between treads and insid walls - all ok.
Comfort say they do not limit lifespan but obviously expect tyres to be roadworthy as per MOT.
Have a great Christmas and New Year everyone, best wishes to all.

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[Plumb]

With the date of tyres when a chassis from the manufacturer is delivered to the motorhome builder it could already be 12months old . By the time the motorhomes built , delivered to the dealer and then sold to the end user that might be another 12 months so I guess potentially the date could be as much as 2 and 1/2 years old and never been used !

 

[uzsnowdrop]

I had 4x BF Goodrich fitted to our Campscout a couple of months ago. According to the date marks on the tyres they were manufactured the previous month.
The strong smell of tyre rubber is only now starting to fade.
One inconsequential reason for not having tyres "fresh off the press"

Mixyblob can I ask how you are getting on with the tyres now?

 

[Millcourt]

If I fill my tyres with Helium, will this increase my available payload?

 

[Mixyblob]

Mixyblob can I ask how you are getting on with the tyres now?

We've done over a thousand miles on them so far, no problems, definitely a smoother ride, no louder than the previous tyres just a different sound.
The grip on wet grass is infinitely better as we found out on a sloping campsite. Brother in law has same van but different tyres (vanco 4 seasons) and was sliding all over the place, whereas we had no problems at all.
Its too early to give a definitive yay or nay but so far so its a yay.

 

[Bessy765]

To help prolong the life of tyres if not moving for a while cover them to keep the sun’s rays away. New tyres are usuallly stored inside away from this so even if the date stamp is a couple of years old they should be fine.

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