My 2006 gas coach was factory build with 50 amp service and room for multiple batteries. I have 2 GC2 batteries for the occasional need when off the grid but I could fit four if I reconfigure the battery tray. The demand for front and rear AC is driving the 50 amp need. The rear AC in my coach the first owner installed. I don't recall seeing a gas rig with a residential fridge which would drive a need for a bigger bank but I haven't been looking either.
For the past couple of years Ford has been using 22.5" tires on the 22, 24 and 26K lbs. GVWR chassis. Leaves 16, 18 and 20.5 lbs. chassis with 19.5" tires. Suspect the size increase wasn't so much consumer demand but to better match the load capacity of the axles. My 18K GVWR chassis has more load capacity in the 19.5" tires than the axles.
