Hello, I hope I have no mistake in thinking, here is a calculation example: Let’s take a tire with 2.5 bar filling pressure, together with the ambient pressure of 1 bar (1013mbar air column) are therefore 3.5 bar absolute pressure in the tire. Furthermore, it should be clear that the ambient air already contains 78% nitrogen. In the tire with “nitrogen filling” are: 1.0 bar with 78% nitrogen 2.5 bar with 100% nitrogen Power 328:3.5 = 94% For a 100% nitrogen filling the tire would have to be an air conditioner is evacuated, has anyone ever seen it? In a tire with 2.5 bar filling pressure and chargeable nitrogen filling are therefore at most 94% nitrogen, in a tire with normal ambient air but also 78% nitrogen. Do you really notice the difference between 78% and 94% nitrogen filling, only 20% more? mfg chris