New RV and Tire Pressure

+1 on Gary TPMS recommendation. I resisted for a while, stopping in the first half hour of a trip to feel the tire temps. I figured that a TPMS would be just one more thing to worry about. I had one valve stem extension that had a leak and sometimes checking the pressure would start a leak. I realized that I was doing a lot of extra worrying. After all, I have TPMS on both cars, so why not on the bus?

Next purchase ScanGauge-D.

Do yourself a favor and buy one of the add-on remote tire pressure systems. They have warnings for low and high pressures that you can set. SO MUCH peace of mind with these. Tires virtually never fail if they are properly inflated and especially with duals if you get complacent and don't frequently check pressure you can get into trouble. Also, you could check pressures and immediately pick up a nail. The remote sensor will let you know before damage is done....

On my coach the tire manufactures manual and Winnebagos manual said to run my Michelin Tires at 75 psi rear and 90 psi front. This did not work for me. I was getting rear tire squirm at 75 psi in the rear tires. What I did was experiment with air pressure in the tires every time I went RVing. I settled on 100 lbs. psi all around! It must of worked because I got 10 years out of that set of tires and two years on my new set of tires at the fore mentioned lbs. psi. And your absolutely right in saying low tire pressure is dangerous. The lower the tire pressure the more heat build up you will have inside your tires.

Just as an example, I followed my own advise here before heading out on the winter trip last year. Tires were at max sidewall (110) until we got weighed. Because of the number of trips from the house to the bus when loading for the trip, I was pretty sure we'd be overweight. Turns out we were 2000 under. Dropped the tires to 95 psi and the ride greatly improved.

Congrats on the new coach. Now it is time for you to learn the basics. One of the most important is knowing how to load your coach.
You and your wife both need to load EVERYTHING in the coach that you think you will need for your travels. This includes food, seasonal clothing, full fuel, some water in the fresh water holding tank, as well as any tools, or other items that you think you may need on a trip.
Once the coach is loaded, then you need to take it somewhere to get all four corners weighed with all occupants in their seats. Most coaches handle better if the front axle is loaded close to maximum. You also want to make sure that the side to side weight is pretty close. This is where you can start to shift items around to achieve the right weight and balance.
This exercise will let you know IF you can take everything with you, or if you now need to start leaving some things behind because you have exceeded the maximum weight of the new coach.
Only after you have done this can you go to the tire chart and get the exact tire pressure you should be using for the load you are carrying. Most owners will add another 5PSI for safety.
Welcome to the RV world and now you need to do everything to have a safe journey.

Over pressure as long as it's not over the tire or wheel spects for sitting , undriven , "cold" is not dangerous, other than handling being rougher. Until you weigh using the higher pressure is fine. Better to be a rougher ride than a blowout from under inflation .. One of the number one reasons for tire failure.

Be aware that motorhomes can have weight quite different per side.
My conversion was almost 20 percent heavier on driver side, what considering that all the tanks and batteries where on this side was easy to understand
Tire manufacturers advise to pump the same pressure per axle to avoid mistakes, but I kept the weight difference in mind and always put 5 psi more on the side.
For starting point you can always inflate to max psi rating on the tire and then adjust down when you weight it.

The only correct answer is to weigh the coach when loaded as you will travel, including people.

Best to weight each wheel position and use the heavier wheel position on each axle to go to your tire manufacturer's PSI/load chart. That will tell you the MINIMUM PSI for that load. Most add 5-10 PSI to that minimum

If all you have is axle weights (which you can get at many many places in virtually any town) add an additional "fudge factor" for left/right imbalance.

Unless one has exactly the same coach as you and loads it exactly the same as you, THEY HAVE NO BUSINESS TELLING YOU WHAT PSI IS CORRECT IN YOUR, REPEAT YOUR COACH.

the best way to adjust PSI is to load your rig for travel (water, clothes, food, people, fuel), weigh it (4 corners if you can, otherwise both axels) and then set the PSI based on the tire manufacturer's chart.

The psi on the sticker in the MH is not base don how you will load it once you own it.

First, get the coach weighed with your normal camping gear aboard. A four corner weight is ideal, but axle weights are better than nothing. Then go to the TIRE manufacturer's website and look up what the pressure should be for each tire position. If you got axle weights, divide that in half for each corner, If you have rear duallies, use the dual pressure for each tire.

Most Pilot/Flying J truck stops have a scale. They charge $10 and there's usually enough space to run through the scale twice to get the weight of all 4 corners.

Max sidewall pressure is good until you do the above. Just be aware that the coach will ride like Fred Flintstone's car.

Congrats one the new coach!