Are General Aviation tires filled with Nitrogen?
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.