Has anyone tried nitrogen in air forks?

aees
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10/10/2017 7:48am Edited Date/Time 10/10/2017 7:49am
I have run it in my CV AER fork. In percentage wise it made quiet big difference.
Constant increase in pressure with normal air was 3-6psi in upper chamber, and 11-13 in lower chamber. This is during first session.

With Nitrogen it was 1-3, and 7-9 maybe in lower chamber.

So the extra above 76% for sure makes a difference.
aees
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10/10/2017 7:58am
Braaaphole wrote:
This is exactly why I posed the question, it's got some people thinking. I'm an engineer as well, though electrical. I'd suspect the volume of air...
This is exactly why I posed the question, it's got some people thinking. I'm an engineer as well, though electrical.
I'd suspect the volume of air used in forks isn't enough to see a real improvement if filled with nitrogen. While the properties are different from air, it's not very much. I would suspect that there would be a measurable difference in pressure, though minimal. I think the biggest gain would come from the lack of moisture.

I'd be very interested to see a true test done with a pro level rider that would really get the components heat saturated over a 20-30 minute moto.
Dont need a pro for that. New Cone Valve AER fork has huge problem with increasing pressure in lower chamber. This is due to the small volume.

Started out my days of testing (have about 30 days/hours of testing on them) with for example 160psi upper chamber, 175psi lower chamber. After 10min pressure was up to ~164psi in upper ("ok" increase" but for sure noticeable), and ~188psi lower chamber (un-rideable).

Much better with nitro (almost cut the increases in half), but lower chamber still to bad to actually work for someone that does not have nitro-tubes and mechanic and excel sheets to manage air pressures for various times of day and temps.

Talked to WP USA and Europe about it, their solution was to bring a stand to the pitlane and reset it after first 10-15min of riding. I got it exchanged to spring based CV fork...
10000hrs
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10/10/2017 9:57am Edited Date/Time 10/10/2017 10:09am
rmoto003 wrote:
PV=nRT The only difference between the two would be n n is the number of moles The n factor would be smaller for pure nitrogen (pretty...
PV=nRT

The only difference between the two would be n

n is the number of moles

The n factor would be smaller for pure nitrogen (pretty sure about that) so the Pressure*Volume would change less with increase in T
Aircraft struts are "air shocks". The force is governed by the polytropic gas law:

PV^gamma = constant

https://en.m.wikipedia.org/wiki/Polytropic_process

For application to suspension See page 13 or Eq. 3 on Page 14 of

https://digital.library.unt.edu/ark:/67531/metadc56410/m2/1/high_res_d/…

Happy studying,

An Aerospace Engineer
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Mike_Lawlor
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10/10/2017 11:29am
I use nitrogen for my job all the time so I have it ready available and free to me. I used it in my 13 Honda forks and it never changed more than 1psi throughout the day and it also never leaked out over time. I was religious about checking the pressure every time I rode and it was always the same. For it to work properly though you do need to compress the fork completely and let all of the air out of it. I did this proses twice to ensure there was in fact no "air" left in my forks. I do refridgeration work and like some one else stated we use nitrogen to purge the lines while we are brazing to prevent oxyadation in the piping. We also pressure test with it because it is a dry gas and is not effected by temperatures for the most part. Just my two cents from a HVAC guy who races the A class. Cheers.

The Shop

crowe176
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10/10/2017 12:09pm
Bultaco wrote:
I use 76% Nitrogen all the time.
76% of the time, it works everytime?
MohMoto14
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10/10/2017 12:32pm
rmoto003 wrote:
PV=nRT The only difference between the two would be n n is the number of moles The n factor would be smaller for pure nitrogen (pretty...
PV=nRT

The only difference between the two would be n

n is the number of moles

The n factor would be smaller for pure nitrogen (pretty sure about that) so the Pressure*Volume would change less with increase in T
Someone please let me know when a mole is explained on here, that would be solid entertainment.

10/23/17 merry mole day
Spurdo
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10/10/2017 1:22pm
FHKRacingZ wrote:
Anytime you heat a gas you will experience pressure change. Thermal transfer rates of different gases is huge, and why truckers keep a consistent blend for...
Anytime you heat a gas you will experience pressure change. Thermal transfer rates of different gases is huge, and why truckers keep a consistent blend for efficiency in their tires. Outgassing through the rubber is a old wise tale. Yes a tire can outgas but not nearly at the rate you will destroy it with use lol.


The guy claiming nitrogen makes no difference than regular atmosphere must of missed a basic chemistry class. Atmospheric air, even if ran through a filter dryer, is totally inconsistent. Being inconsistent means different blend of gases that expand at different rates...Which means finding consistency can be hard.

On warmer days, you will heat soak the metal and transfer external heat into your air chamber (More than what is already generated by the mechanics of the fork). That is why using a 100% tested, inert gas is huge..Eliminates one variable from why your fork may/may not be working how you want.

Sincerely,

An Engineer.
Could you name a few things you engineered? Or you the type of engineer that drives a train? Just curious, XDDDDDD
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ando
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10/10/2017 2:53pm
Just to clarify something...

Nitrogen doesn’t have special anti-moisture properties. It’s free of moisture because of (a) the way it’s made, and (b) it’s packaged for sale to make sure it has no moisture.

Who gets their air from a source that’s been handled the same way? Almost nobody. At best the compressed air system at Joe’s Garage on the way to the track might have an old busted arse water trap that gets drained every few days. At worst I might hook up my on board compressor in my 4x4 with absolutely no drying on it at all.

On those hot days in summer when the humidity is reaching 90% or more the air has just about as much moisture is it can physically hold. Think about what might happen when you roll the bike out of the garage in the morning, check the tyre pressures and add some air. That warm humid air hitting the cold surface inside the tube is not dissimilar to pulling a cold can of Coke from the fridge and letting it sit on the table for a few minutes.

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r.sal923
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10/10/2017 4:48pm
I bought A bike with coil springs in the forks, I have none of these problems you guys speak of.

Sincerely

Yamaha owner.
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RBernardi85
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10/10/2017 7:35pm
I turn liquid nitrogen into a gas through a heat exchanger and pump it almost daily. But I run helium in my airforks.
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linker48x
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12/29/2023 5:55pm

Just like the old Olympia beer ad, "it's the water..."  Nitrogen is the cheapest dry gas that will work for this application.    

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spitinabucket
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12/30/2023 7:41am
tempura wrote:
The only thing that made a real difference with my air forks was putting the glide kit in. Air forks by their nature have more resistance...
The only thing that made a real difference with my air forks was putting the glide kit in. Air forks by their nature have more resistance. Eliminate as much of the resistance as possible and they start feeling like normal forks.

I have 2023 xcf350 and also did the glide kit and from another thread I did try the motor oil for more lubricity, I am very happy with air forks this is the second bike I've had, once you dial them in they work great.

Sincerely,

A jackass engineer - jack of all trades master of none

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dsc131
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12/30/2023 8:13am

My buddy runs helium due to its monatomic properties…says it helps him clear the finish line double,

12/30/2023 10:24am
Bultaco wrote:
I use 76% Nitrogen all the time.

Well, closer to 78% actually... 

And given a 'Nitrogen' filled tyre will actually be about 93% Nitrogen, the difference is negligible.

 

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MPJC
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12/30/2023 10:34am

I put helium in my tires and air forks. Makes them lighter and I can jump farther. 

Beagle
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12/30/2023 1:19pm

Not sure about air forks but for tires, using nitrogen is marketing, or at best it's a way to get dry gas, that's all.

Indeed moisture makes all the difference, that's why MotoGP factory teams use tyres with two air valves so they can flush dry air between every session to make sure they use air as dry as possible. They use 22 tires per weekend, typically kept around 90 °C in tire warmers, they go over 100 °C for the front and 120 °C for the rear. They do have the budget for nitrogen, if it could give them the tiniest improvement in performance they would absolutely use it.

https://x.com/PeterBom4/status/1643218642044178432?s=20

MX683
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12/31/2023 6:03pm
sgrimmxdad wrote:
Why aren't more of you riding with air in your shock instead of nitrogen LOL! I have my own suspension shop now, we talked about it...
Why aren't more of you riding with air in your shock instead of nitrogen LOL!


I have my own suspension shop now, we talked about it trying nitrogen in air forks, but after discussing it with my guru, "pun intended" and hearing his past experience with it, we realized it was not enough of a difference to bother.

I understand why HRC or other factory teams would use it. On that level at the end of a 30 min moto it may make a slight but enough of a difference to use it... 99.9% of riders would never know a difference....

Have you ever tried air in a shock instead of nitrogen?

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