Nitrogen myths

Keith72 wrote:

Isn't the nitrogen molecule larger than oxygen?Therefore less bleed off over time.

MotoTribology wrote:

No, N2 has a molecular weight of 28 compared to O2's 32. I believe (though don't quote me on this) it also has a triple bond...

No, N2 has a molecular weight of 28 compared to O2's 32. I believe (though don't quote me on this) it also has a triple bond rather than a double bond, making the two atoms even tighter to one another.

NickoBrap wrote:

Yo momma so fat, when she gets in your car, she splits the triple bond of the nitrogen atoms in your tires, and levels every structure...

Yo momma so fat, when she gets in your car, she splits the triple bond of the nitrogen atoms in your tires, and levels every structure within a 5 miles radius in a nuclear blast.

T-Unit179 wrote:

Helium in tires equals less sprung weight.  Thats how I won my local county fair races 😂🤣

CBE wrote:

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric...

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric air unless you are collapsing the bladder or moving the piston all the way down prior to charging. All the nitrogen is doing is compressing the air in the shock. Gases compress. Liquids cannot be compressed. Is it a better idea to use nitrogen? Maybe. But unless you are filling the bladder or tire from fully deflated and flat it’s not 100% nitrogen in there.

ando wrote:

What about dry air?  Would that be ok?

Jkawi wrote:

If you understand the science, use whatever you KNOW works. If you don't understand anything like shorty, then don't be a hack job and absolutely, willingly...

If you understand the science, use whatever you KNOW works. If you don't understand anything like shorty, then don't be a hack job and absolutely, willingly get conned into using nitrogen.

My point is, this isn't magic. It is based on facts you learned the basics of in high school. FACT: YOU will never know the difference in a bladder type shock. In emulsion shocks, there is an infinitesimally small argument for corrosion inhibition.

What is the compressibility factor for air vs nitrogen at the pressures and temperatures you see in a shock? people that say air can't be used, use the math and show me how much of a difference it represents in a hot shock @ 150psi

ando wrote:

My question was rhetorical, I understand the science.  The only practical difference between bottled nitrogen and regular compressed air is that in the majority of cases...

My question was rhetorical, I understand the science.  The only practical difference between bottled nitrogen and regular compressed air is that in the majority of cases the compressed air doesn't have the moisture removed.  This isn't an inherent characteristic of nitrogen; it's simply due to the way it is produced.  It is pretty easy to dry the air if you want to, in circumstances where moisture is a concern, and the performance will be the same.

With regard to compressibility, nitrogen and air both follow the ideal gas laws and there is almost no measurable difference, unless you are talking about really high pressures, way above what is in a shock, and even then while it's measurable, there is no practical difference.

Really the only applications where pure nitrogen has any benefit over dry air is where there is a risk of reaction or combustion in the presence of oxygen.

Having said all that if it's easier, cheaper and more practical to buy bottled nitrogen than try to obtain dry compressed air then there is no harm in doing it.

BTW you obviously understand the differences so this isn't aimed at you, but there is clearly a lot of misunderstanding about this topic.

CBE wrote:

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric...

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric air unless you are collapsing the bladder or moving the piston all the way down prior to charging. All the nitrogen is doing is compressing the air in the shock. Gases compress. Liquids cannot be compressed. Is it a better idea to use nitrogen? Maybe. But unless you are filling the bladder or tire from fully deflated and flat it’s not 100% nitrogen in there.

FGR01 wrote:

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize...

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize it while the flush is ongoing.  Kinda like how it is possible to completely bleed air from your brakes without having to vacuum the system first.  The nitrogen displaces the ambient air just as brake fluid does.  

CBE wrote:

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric...

I love when people say you should only use nitrogen for a shock bladder. Realize that 90% of the air in a shock bladder is atmospheric air unless you are collapsing the bladder or moving the piston all the way down prior to charging. All the nitrogen is doing is compressing the air in the shock. Gases compress. Liquids cannot be compressed. Is it a better idea to use nitrogen? Maybe. But unless you are filling the bladder or tire from fully deflated and flat it’s not 100% nitrogen in there.

FGR01 wrote:

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize...

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize it while the flush is ongoing.  Kinda like how it is possible to completely bleed air from your brakes without having to vacuum the system first.  The nitrogen displaces the ambient air just as brake fluid does.  

Last2Stroke wrote:

"The nitrogen displaces the ambient air just as brake fluid does."No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.If...

"The nitrogen displaces the ambient air just as brake fluid does."

No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.

If the bladder is full of air and you pressurized it to 150psi with 90% nitrogen, the percentage of nitrogen in the bladder will change from 78% to 89.2%, because you have added nitrogen to the air. The bladder still contains 10.8% oxygen, carbon dioxide, water, and other gases.

FGR01 wrote:

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize...

As I posted above, that is not exactly true.  It is possible to flush the bladder with nitrogen first and then close a valve and pressurize it while the flush is ongoing.  Kinda like how it is possible to completely bleed air from your brakes without having to vacuum the system first.  The nitrogen displaces the ambient air just as brake fluid does.  

Last2Stroke wrote:

"The nitrogen displaces the ambient air just as brake fluid does."No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.If...

"The nitrogen displaces the ambient air just as brake fluid does."

No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.

If the bladder is full of air and you pressurized it to 150psi with 90% nitrogen, the percentage of nitrogen in the bladder will change from 78% to 89.2%, because you have added nitrogen to the air. The bladder still contains 10.8% oxygen, carbon dioxide, water, and other gases.

ando wrote:

Throughout this whole thread there’s a lot of basic principles that have been overlooked or ignored.

Last2Stroke wrote:

"The nitrogen displaces the ambient air just as brake fluid does."No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.If...

"The nitrogen displaces the ambient air just as brake fluid does."

No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.

If the bladder is full of air and you pressurized it to 150psi with 90% nitrogen, the percentage of nitrogen in the bladder will change from 78% to 89.2%, because you have added nitrogen to the air. The bladder still contains 10.8% oxygen, carbon dioxide, water, and other gases.

Last2Stroke wrote:

"The nitrogen displaces the ambient air just as brake fluid does."No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.If...

"The nitrogen displaces the ambient air just as brake fluid does."

No it doesn't, nitrogen mixes with the air, you do realize "air" is 78% nitrogen.

If the bladder is full of air and you pressurized it to 150psi with 90% nitrogen, the percentage of nitrogen in the bladder will change from 78% to 89.2%, because you have added nitrogen to the air. The bladder still contains 10.8% oxygen, carbon dioxide, water, and other gases.

FGR01 wrote:

Go back and pay attention to the word flush.   Yes, if you don’t take measures to remove the ambient air first the nitrogen will simply...

Go back and pay attention to the word flush.   Yes, if you don’t take measures to remove the ambient air first the nitrogen will simply mix in.  But if you flush it sufficiently first it will remove the ambient air more and more until there’s essentially none left, raising the nitrogen percentage above your calculation.  

Last2Stroke wrote:

How do you "flush" the air?

Last2Stroke wrote:

How do you "flush" the air?

FGR01 wrote:

I built a charging setup that has a release valve. I let the nitrogen flow from the bottle through the charging setup and bladder to flush...

I built a charging setup that has a release valve. I let the nitrogen flow from the bottle through the charging setup and bladder to flush or purge the ambient air out the valve.   Then I close the valve mid-flow and set the final pressure.  Not a perfect vacuum, but it’s certainly getting the majority of the ambient air out.