New tires?? Heck I haven't bought a 'new' set of tires for any of my 1st gens EVER. Got my first one in about 2000 IIRC. I either come across used ones better than what I got for trade or cheap, or just buy a whole truck be it parts truck or runner that already has a good set of tires on it . "When the tires start looking bad, time for another parts truck".
On the subject of nitrogen filled tires. I haven't come across a free oxygen regulator yet . So I just have a large nitrogen cylinder sitting in the garage for now. I like the idea of it being completely dry. Certainly that has to be good for tires. Not to mention having that drying action of nitrogen to dry, blow off, purge, or you name it to whatever. Did I mention it's free for me? hehe