A repeat, but individual axle weight is so important when accessing manufactures tire pressure charts, I'll repeat and summarize again.
1) Get ready for travel. But, if you only travel with half a tank of water, for this time, top off. Also top off on fuel and LP. And not a bad idea to even half 1/2 tank each Grey/Black too.
2) Obtain four corner weight. The best way is the individual scales. But if at a larger truck stop type scale. Do get your full axle weights, the straddle the scale and get that sides axle weight, and do the math.
3) Use the highest weight per axle side, when accessing the manufactures PSI charts.
>Important that if your seeing an 'axle weight' on the manufactures PSI charts, that
when you do not use the sum of the two sides of the axles weight. Take the highest
axle weight, and multiply it by 2, and use that as your axle weight. (It will be higher
then the sum of the actual side by side weight.)
4) When I'm accessing the manufactures PSI charts. If I'm within the upper 25% of a lines weight range - I bump up to next higher weight on the chart.
5) I multiply the recommend lowest pressure from the PSI chart by 10%, then round up to the next highest ending "0" or "5" number. Say the chart says 90 PSI, I add 9 PSI to the 90 for 99, then round up to 100 PSI. (This is just my way of doing it, as I find it's easier when airing, or having someone air your tires, to have a 95, or 100, or 105, etc PSI.
These added contingency PSI's are just that - contingency. Allows for coach weight creep while traveling. Allows for some PSI loss while traveling, and still you should be above the minimum recommended PSI setting by the tire Manufacturer.
And of course, never exceed the maximum PSI for your wheel tire combination. Stop at that level, if the above rounding up exceeds that value.
I also recommend doing the math to adjust the PSI settings when tires are cold, per outside ambient temperature. On hot days, adjust PSI lower, on cold days, adjust PSI higher. Each tire manufacturer has their own spec, but an average rule of thumb is 2psi for each 5F degrees difference.
I also recommend checking of your Tire Pressure Monitors reported PSI, in comparison to what you just set your tires too. (I've seen some, with 5 degrees difference. I note this down, like LF -3 PSI, LR +1 PSI, etc. And I've seen as high as 5 PSI off from the setting and the reading of the TPM.) (Don't stress this too much, as usually their within a range of + o = 2-3 PSI, well within the 'contingency range' of the extra PSI. But say the + 5 PSI, I remember what position that is in, and factor that when traveling.
And I think most of us do a daily walk around before heading out, and at rest or fuel stops too, and do a visual inspection of our tires. (I pointed out a bulging, slipped or broken cord, bump on a front tire to a gent next to me fueling, just last month. So visual inspections can help you save a blowout.)
IMO, overall today's tires are very robust, and usually have plenty of capacity to handle our coaches. Sure some of the BIG BOY 45' coaches are rolling along with quite a heavy load. And yes, some coaches have left the factory with overloaded suspensions and tires to start with. So know your coach, know your weight ranges and CCC's etc. But typically most of us are doing pretty dang good...
Take care of your tires. As those little patches making contact with the ground, are the only thing that turns you, stops you, or accelerates you down the road. Tires matter, and are an important and unfortunately often neglected part of motoring. RV'ing, and auto's too
All subject to doing what you feel is right. But that is how I've evolved in the coach world.
All my best to all, be safe, have fun,