Track tires -Nitrogen filled tires vs air. Mixing?

[Krman68]

my track tires, Hoosier R7s were filled with nitrogen when mounted. I know the advantages of fillinf with them for pressure stabilith but

Is it safe to add air to a nitrogen filled tire or mix nitgrogen with air to increase pressure? I have one race tire that lost its pressure ans want to just fill it with air. Think its Ok? I realize air will vary in pressure as used.

I’d like to hear everyone’s thoughts on this

Thanks

 

[Big Black]

No difference, just get a good steel stem and spit on it. You are going to put air in it and let it out at the Event, and your bubble/compressor is going to be filled with O2 probably. (IMSA racers feel free to chip in)