Nitrogen tank, wt heck?

[K85 Octane]

Did I miss something? I don’t know what happened but I hope I didn’t make a costly mistake.

I bought a nitrogen tank and have it on a swap account with Airgas. I hope I’m not stuck with the wrong size tank.

History: When I went to the Rubicon I borrowed an aluminum nitrogen tank. I don’t remember the size but I don’t think it was much bigger than my steel tank. When I aired up, we went from 13psi to 36psi. Four tires, 38x15.5x18. Finished those and someone else borrowed the tank to fill 40x13.5 tires. Have no idea what was left after that.

Yesterday I took my tank, gauge reading 2,000psi and managed to air up 1.5 tires. 40x13.5x17. From 15 to 36. The second tire I got it to 25psi. What the hell happened? Tank is about 12” tall before the bend.

 

[dyeager535]

Just making sure I understand, you are thinking it didn't air up many before running out?

I checked into this before, nitrogen cylinders hold nowhere near as much "gas" (by cubic foot and thus equivalent cylinder size means a lot less volume) than CO2.

That said, you are talking about large tires with a lot of volume, regardless.

Since I like to nerd out with numbers...a ~14" (5lb CO2) cylinder filled with nitrogen contains 14.5 cubic feet. That same cylinder filled with CO2 is 43.7 cubic feet.

 

[Wes Harden]

Elevation. Rubicon is much higher than Rancho

 

[nvrenuf]

Correct me if I’m wrong but isn’t the gauge less useful than one would think on a tank like this? Aren’t these measured by weight rather than pressure?

 

[HankScorpio]

I use the larger size for HVAC leak testing. It does start at the 2000-3000 range and I only am filling 7/8 and 3/8 lines. It gets used up fairly quickly, maybe 10 system checks. My tank probably holds 10 times as much gas as the one you have, its the 30 inch or so tall size. I think you need a larger tank, that ones tiny. Its a pretty expensive way to fill tires, especially big ones.

 

[1300obo]

Correct me if I’m wrong but isn’t the gauge less useful than one would think on a tank like this? Aren’t these measured by weight rather than pressure?

That's definitely the case with liquid co2. I used to have 2 50 lb tanks for paintball. You determined when you were almost out by weight not pressure

 

[dyeager535]

Correct me if I’m wrong but isn’t the gauge less useful than one would think on a tank like this? Aren’t these measured by weight rather than pressure?

Nitrogen is typically stored as a gas, so weight apparently isn't how it's measured. Same as helium, argon, oxygen, etc.

CO2 is generally stored as a liquid, which is why there is so much more in a tank, and why it's weighed (like propane).

 

[Chickntrk]

I put air in my tires, haven’t run out yet.

 

[Fastereddie]

I put air in my tires, haven’t run out yet.

I was waiting for that

 

[ktmoutfront]

That tank is way too sall for your tires. As has been stated, Nitrogen is stored as a gas, you need a larger tank than with CO2. I have used my larger tank for shocks only. Been through 3 of them over the years.

 

[Tnsejed]

Like everybody else said, you wanted a CO2 tank, not a nitrogen tank. 10lb CO2 will get me 3.6 fills on 42" tall treps for reference. So, nitrogen for shocks, CO2 for tires.

What we have found here in Colorado is to not use airgas with CO2. Use a grow supply place to refill them. Airgas generally will only fill with food grade CO2, and its expensive. 5 bucks for a refill at a grow place.

 

[K85 Octane]

Yeah guys, that’s why I’m hoping to swap this for a larger tank and not eat the price difference too bad.

I mentioned an aluminum tank in the first post, simple because I don’t know what size it was. I borrowed it from an HVAC tech. It didn’t seem all that much bigger. Considering how many tires of similar size I aired up after the Rubicon trip, why couldn’t I get more than 1.5 this time?

That’s where the shock and question came from. I’m just trying to do a simple air tank for those trips that need highway driving to get home. (Drove 15psi during Moab trip, load on trailer, go home)

So what did I do wrong? I thought nitrogen was the bees knees and would “air up” more tire per same size bottle than CO2. Until I figure out compressor/tank OBA, the nitrogen tank sounded good. (Plus I can use for small pneumatic nail gun work)

 

[Wes Harden]

Nitrogen is great for tires because it's dry, and doesn't change much with temperature. keep your tires from Roting out from the inside.
You ever see a gas cylinder next to a power pole? That nitrogen, the power company has it plumbed into the power line insulation to dry them out.
Need a nitrogen cylinder? Check out power poles

 

[dyeager535]

So what did I do wrong? I thought nitrogen was the bees knees and would “air up” more tire per same size bottle than CO2. Until I figure out compressor/tank OBA, the nitrogen tank sounded good. (Plus I can use for small pneumatic nail gun work)

Nope, other way around. CO2 stored in liquid form goes through a phase change when it's released from the tank. A liquid turned to gas takes up far more volume.

Nitrogen is great because it is very temperature stable in tires (pressure doesn't change with temperature) and it's molecules don't pass through the rubber as easily as CO2. There is some talk that CO2 hurts tires from the inside, but I couldn't get a major manufacturer to state that explicitly.

Nitrogen is more expensive and doesn't have nearly as much fill capability as CO2 in the same size container. CO2 is very cheap, purchased from the right places.

 

[TerryD]

I had a pretty cheap CO2 setup in my K5. It worked good but I swapped over to a $60 Chinese compressor that a lot of friends had good luck with for the Xterra since I didn't have to worry about storing the cylinder.

Edit: price has gone up a good bit.

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