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Long story short, I'm working on a concept for a book.

We all know why commercial aircraft have nitrogen tires, but my question is if GA aircraft have nitrogen tires, or are they just filled with helium, oxygen or any other gas? My theory is that commercial aircraft are heavier, so probably need nitrogen tires, whereas general aviation aircraft are much lighter, so wouldn't be needed to withstand as much surface friction, meaning it may not need a more heat-prone gas for the tires, like nitrogen.

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  • $\begingroup$ See also Does Nitrogen inside commercial airliner wheels prevent blowouts on touchdown? for further discussion on why some aircraft tires are filled with nitrogen. $\endgroup$ Jun 25 '20 at 0:38
  • $\begingroup$ @Greg Hewgill: I've edited it. Thank's for the suggestion. $\endgroup$ Jun 25 '20 at 0:41
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    $\begingroup$ No worries. I mostly wanted to link to that other question because not everybody knows why nitrogen is used in the first place. $\endgroup$ Jun 25 '20 at 0:42
  • $\begingroup$ You would never put aviation grade oxygen in a tyre. Oxy and oils/greases when mixed causes combustion. Minimum distance these should get is 20m unless it's installed in an approved container (pressure cylinder or converter) on the aircraft. $\endgroup$
    – Craig
    Jun 25 '20 at 5:13
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Although I can’t speak for every GA pilot, the aircraft that I have flown have had their tires inflated from an ordinary air compressor. We have used handheld battery operated compressors, floor standing compressors, small-tank mobile compressors, and hand carried compressed air storage tanks.

The max speed that we actually use the tires is under 100 mph. The max weight that we carry on them is under 6000 pounds.

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  • $\begingroup$ Just for further clarification, what aircraft do you fly? $\endgroup$ Jun 25 '20 at 0:53
  • $\begingroup$ SportCruisers; Cessna 152, 172, & 182s; Piper Cherokee, Warrior, Archer III, Seminole, Arrow, Apache, & Aztecs; Beechcraft Duchess; Robinson R22s $\endgroup$
    – Dean F.
    Jun 25 '20 at 1:00
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It comes down to what's available. If your airplane is at a facility of some kind where there is a dry nitrogen bottle available to you, you will use that. But you will only find those kinds of bottles at maintenance shops. Most of the time you are using regular compressed air as Dean says.

I inflate the tires of my plane with whatever compressed air source is handy, to about 25-30 psi. Small GA tires, which generally have inner tubes, lose significant pressure over time because of the small volume and the presence of oxygen which permeates the rubber more readily; a lot more than car tires, about 2-3 psi a month I'd say. Nitrogen would reduce the pressure loss a bit, but compressed air is cheap and the tires are pretty tolerant of the pressure variations, and they don't get very hot so thermal expansion isn't that big a deal.

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  • $\begingroup$ “ It comes down to what's available.” - Interestingly enough, I can get my car tires filled with nitrogen at my local Costco any time I want. But, my local FBO fills aircraft tires with a handheld, battery operated compressor. My local flying club uses a 1-gallon mini-compressor. Doesn’t that seem a little backwards? I wonder if the FBO saves the nitrogen for their jet traffic? $\endgroup$
    – Dean F.
    Jun 25 '20 at 3:25
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    $\begingroup$ Well, nitrogen in car tires is called "marketing" where there is money to be made on something completely worthless, from an actual real-world practical standpoint. because people hear that racing and airliners do it. $\endgroup$
    – John K
    Jun 25 '20 at 4:20
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    $\begingroup$ @John K: True. And consider that if oxygen does diffuse out of the tires faster than nitrogen does, after topping up the pressure a few times, the gas in there is going to be pretty close to 100% nitrogen anyway. $\endgroup$
    – jamesqf
    Jun 25 '20 at 5:17
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    $\begingroup$ Air is free, easy to pump into tires and works very well. Seems like a winner to me. $\endgroup$
    – GdD
    Jun 25 '20 at 8:26
  • $\begingroup$ As made clear in the link provided by Greg Hewgill, there are valid reasons why commercial airliner tyres would want pure nitrogen. The same reasons might apply to a racecar. But for the majority of personal cars and GA aviation, plain old air, which is 78% nitrogen, seems just fine to me. $\endgroup$
    – Stu Smith
    Jun 26 '20 at 4:56

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