Mr. G. O. M.,
You can certainly weigh the whole coach but that will not help you with four corner weighing to get the correct tire pressure.
I found a moving company with our previous coach that allowed me to do 'four-corner' weighing on their scales for about $12.
On our current coach, I was at a Prevost seminar at a service facility that weighed the coach for me. They had the type of lift where they roll up the machine to each axle location (6 machines) that lift the coach all at the same time.
I recorded each wheel weight, subtracted the machine weight of 360 lbs. per position to get my actual corner weight.
Our max. axle weights are:
Front: 19,000 lbs.
Drive: 22,500 lbs.
Tag: 14,000 lbs.
Total--55,500 lbs.
I was a little over when I had a full tank of fuel (230 gallons) and full fresh water (189 gallons), so I adjusted on how much water I carry. I quickly become under weight once I burn some fuel.
I see the CAT scales at most fueling stations and used them a couple of time with the previous coach just to see how much the whole coach weighed. I was at just over 40,000 lbs. on that coach.
I would assume the reason CAT scales are located at fuel stations is that it is easy for the truckers to weigh after picking up a load to see if they are in compliance. I would think they want to see if they are legal before going through a weigh station. Unless I'm missing something, I'm sure a 'trucker' will pop in to explain the scales.
Safe travels,
MM.