Ron, Each tire on an axle must have the same pressure. Barry
When I had a 2010 model 2350 the fresh water tank was under the bed at the rear, passengers side. The gray tank was under the fresh water tank also on the passengers side. The black tank was on the drivers side. On my 2012 model 2552 the black and gray tanks are switched as the toilet has moved from the drivers side to the passengers side of the center line. The toilet has to be over the tank used as the black tank. The fresh water is mid way under the passsengers side bed.If you look at all the layouts you will see the black tank changes by where the toilet is located. You can tell this by looking at the capacity of each tank. PC only uses two tanks, the one 35 gal. that fits under the passengers side behind the axle and a smaller 23 gal. tank the fits under the sani-con on the drivers side. The fresh water tank changes size based on the layout.
Ron D.: I called Michelin on that very question and they had a very quick answer....take the heaviest corner and inflate both tires (double if rear) to that PSI. Thanks