[JimD]

I see no reason to refuse to allow somebody to fill your tires with 100% nitrogen. I also see no reason to upgrade from 80% nitrogen to 100% if I have to pay more to get it.

There are benefits but none worth paying for. It will leak out a little slower, it will cause the tire to run a tiny tiny amount cooler. It may cause the "rubber" in the tire to degrade more slowly (who has seen a tire replaced for degradation from the inside out).

Some tire places apparently buy bottles of very high pressure nitrogen and save wear and tear on the air compressor. If they can also get a few dollars from customers for the nitrogen, that is even better.

Jim