Nitrogen filling

[Nashcat]

Skip buying the tank. Get the high pressure regulator and go to almost any welding shop and get them to top it off with Argon. We used Argon in hydraulic accumulators for many years, simply because we always had tanks of Argon in the maintenance shop.

John

 

[Grand Rouge]

I have had shocks and tires inflated with Nitrogen at my local FBO......nitrogen used in aircraft oleo legs. Free too.

 

[SMSW]

For tires, it seems that its not as easy as you claim to get compressed air that's dry enough, because none of the race teams do that, they all use Nitrogen.

I'm not claiming its easy. I really don't know and I'm asking. How dry does air have to be inside a tire to not create problems? And how much moisture is present in compressed air fed to paint spray guns in good auto body shops?

My seat of the pants guess is that race teams use nitrogen bottles because it's relatively cheap, convenient, and needs no maintenance (other than making sure the bottle is full or has enough gas for the race). I also would posit that a compressor regulator fitted with filter and dryer stages will provide air that is dry enough but is one more bit of maintenance for the race/pit team. Someone has to make sure the compressor is plugged in and working, the filter is purged of water and the desiccant is changed regularly. Easier to just grab the N2 bottle hose.

 

[Bmacleod]

I'm not claiming its easy. I really don't know and I'm asking. How dry does air have to be inside a tire to not create problems? And how much moisture is present in compressed air fed to paint spray guns in good auto body shops?

My seat of the pants guess is that race teams use nitrogen bottles because it's relatively cheap, convenient, and needs no maintenance (other than making sure the bottle is full or has enough gas for the race). I also would posit that a compressor regulator fitted with filter and dryer stages will provide air that is dry enough but is one more bit of maintenance for the race/pit team. Someone has to make sure the compressor is plugged in and working, the filter is purged of water and the desiccant is changed regularly. Easier to just grab the N2 bottle hose.

It is my understanding that nitrogen is not affected by temperature as much as regular air. So, when the temperature goes up the pressure doesn't change as much and I would imagine that's the single biggest reason race teams like nitrogen, for better control of pressures

 

[Andrew Shadow]

Aircraft tires use nitrogen for two main reasons;
- It's pressure varies less with temperature changes than ambient air does, so it is more stable under greater temperature ranges.
-It is inert. It won't fuel a fire in the landing gear bay when the tire explodes.

Race cars use it mostly because it offers less temperature change induced pressure variation.

My experience is that shocks that are in need of nitrogen also need other servicing as well. I would not invest much effort or money in to filling it, but would put that money towards a rebuild. If you can get it done on the cheap, than by all means.

 

[dwalby]

Aircraft tires use nitrogen for two main reasons;
- It's pressure varies less with temperature changes than ambient air does, so it is more stable under greater temperature ranges.

Race cars use it mostly because it offers less temperature change induced pressure variation.

It is my understanding that nitrogen is not affected by temperature as much as regular air. So, when the temperature goes up the pressure doesn't change as much and I would imagine that's the single biggest reason race teams like nitrogen, for better control of pressures

yes, this is true, but all gases follow the ideal gas law pretty closely at the pressures used in tires so its not really the air itself that causes the pressure increase differences. All gases change pressure at about the same rate. The downside of plain compressed air is the water vapor that is injected into the tire by the compressor goes in as a liquid, then when heated in race conditions it turns into a gas and that causes a significant change in pressure. Since Nitrogen is dry, it has the advantage of no water vapor. It seems a bit hard to believe that enough water vapor can be in the compressed air, but that's the story I've always been told as to why Nitrogen is used by race teams.

 

[sirbike]

@Andrew Shadow quote
In post below

This answer fits with the short answer that I got from the suspension shop.
If it’s low, it has a leak, time for a rebuild.
I would think it could be like a car tire and need a maintenance top off now and then.
I measured the pressure with a no loss valve. That would be no loss when adding air. Taking a measurement costs about 1 or 2 psi.
It was at 140. 150 is spec.
And while the shock hand pump was there I topped it off.
So I went off in this direction because the new shock sagged less than the old shock that was supposed to have been set at the same preload. I figured gas pressure must be the difference.
Whatever the case thanks for the knowledge and thoughts.
As it stands the 06 has a soft total highway comfort ride that is fine.
The 06A with the fresh shock is going to the twisties this weekend.
More on that later.

 

[sirbike]

@Andrew Shadow quote
“My experience is that shocks that are in need of nitrogen also need other servicing as well. I would not invest much effort or money in to filling it, but would put that money towards a rebuild. If you can get it done on the cheap, than by all means.”

 

[Andrew Shadow]

Not much comparison between aircraft and car tires including the presence of moisture in the compressed air, so I would think that the effects of nitrogen would be much different between the two. Advantages of nitrogen are less significant for cars would be my guess, but this is not the correct thread to figure that out.

 

[Chris09]

I have no opinion on the merits of recharging a shock, my guess would be if it leaked down, it will leak again but If you have an AC / Refrigeration guy that you know he'd be able to give your [relatively tiny] shock a shot of N2, everyone here carries a pair of N88 N2 cylinders and a regulator, he'll be able to set it exactly to whatever pressure you ask, and see if it's able to hold pressure, just have an adapter at your connection point that will readily connect to a 1/4 or 5/16 if he's doing a lot of R410A hose from his service manifold.

 

[ThruST]

Got into a discussion a while back with one guy.... 3 series black BMW with toned windows, you know the type. I commented on the green valve nubbles on the tires and I was informed that it is because he paid top Euro for nitrogen. 60 Euro a tire.... "Why?" I ask all innocent. "It´s technology from the aeronautical and spaceflight industry, Nitrogen molecules are larger that oxygen molecules so you keep a filling longer.... All the other guys in the group nodded. "Best there is" I was assured.
"Well" I say. The reason it is used in the aeronautical industry is that at the operating hight of jets the air is -50, -60° and normal air would freeze, that´s the only reason. Then oxygen molecules are in fact larger that those of Nitrogen, and lastly the air that you breath is already 80% Nitrogen, so I would have just bought the green nubbles and be done with it.
Needless to say I was not popular.

Yes nitrogen is used in aircraft because it is dry, where compressed air will have moisture in it and will have a tendency to freeze. However the main reason nitrogen is used in aircraft is for safety reasons, it is an insert gas and will not feed a possible fire like compressed air

 

[RaYzerman]

In a shock, likely you've lost some damping oil past the seals.... check for weepage around the shock shaft. There is a bladder that separates the nitrogen from the oil... if you lost oil, the pressure in the bladder would also decrease...... bottom line, if the pressure is low, best rebuild the shock with new seals....

Check with local suspension shop, Penske parts are readily available, and if they do rebuilds/refreshes, they should be able to handle it easily. If you want to get into shipping, Traxxion will rebuild it. I had my Penske refreshed (leaked out the oil past the seal) locally for $180 Canadian..... not worth it to me to buy any equipment.......