MIKE - All three of my cars/truck are on alum. wheels. Had one tire on the Wife's SUV that would leak from 35 PSI to 25 in 3-4 days. I aired it up every couple days for 5 months. A new set of Firestone's put an end to that, The Bridgestones on my little car & p/u don't leak, but I still check them before every road trip.
Airing tires up is no problem for me, My compressor is aired up all the time, 80 gal of 120+ PSI air would totally inflate most all of the tires I own. But you are correct, Nitrogen is a larger molecule and does slow or stop air leakage depending on how big the leak is. Plus I've heard it lets tires run cooler at high speeds. That's why race cars use it.
STEVE B. - Yep, plowing at night is great therapy. The tractors always seem to run better in the cooler air, not near as many distractions because you only see what your headlights illuminate. Plus on full-sized tractors, you really see how incredible these old tractors are. The exh. manifold glowing a dull red to orange hot, bottom of the muffler turning color too, the sparks flying out the exh, and a faint flicker of flame on hard pulls. Like the night Dad had Terry Warner of Warner's Turbo Shop in Galva/Kewanee area rebuild the inj. pump on the 4010.. It was a sick tractor! Terry got the pump rebuilt, installed & timed about 9 PM. We had the 4010 up in front of the shop under the yard light. Started it up, checked for fuel leaks, then Dad & Terry jumped on and we headed across the road to the neighbor's bean stubble with our little 12 ft disk. I was driving, headed across the yard, down the road and into the field in 7th gear, 10 MPH when our normal disking gear was 5th, about 5-1/2 MPH. I dropped the disk in the ground, pinned the 4010's ears back, full throttle sailing along, down into the hollow and up the other side of the hill. Dad turned the lights off so we could all see the foot of flame coming out of the muffler & 2 ft long extension pipe. The tractor had NEVER run that hard since Dad had it. I turned around on the top of the hill and ran back down then up the hill and we called the pump rebuild a success. Yerry couldn't believe we were running that fast, but he was used to 4010/4020's pulling much bigger disks, 14-16+ ft.