I bought these Tire-Man: Kit #4-6DS Upgrade 18 Hand Hole Wheel one piece stems. I can really only rotate from side to side without changing stems. Having these and my TST 507RV tire monitor has made my 8k mile (so far) trip to Alaska worry free.
Don't know technical answer to your question. This is my 3rd motorhome and I do not rotate. My 2012 Solera 24S came with the fiberglass valve stems where there was no way to check or add air to tires. Dealer told me it was a safety / liability issue on the part of Forest River, because of the many blowouts and damage as some of you have reported in past on this forum.
My dealer, in the Seattle area, referred me to a Les Schwab tire shop which the dealer uses and also does big-rig 18 wheelers as well as motorhomes. The Les Schwab shop installed a nice, flexing, metal, valve-stem extension, which they sell and attaches to the rear wheel covers on my Solera M/H.
I now have 28,600 miles on my Solera M/H and no problems. However, just like a big-rig 18 wheeler driver should do, I am vigilant in inspecting my tires and valve stems and wheel covers pre-trip, on stops, and at the end of day.
I do not rotate tires, because I do not believe there is value in my time and money I would spend to save the tires from wearing prematurely. In my case, the tires and sidewalls would show signs of rotting from the sun and environment sooner than the tread would actually wear to the point of needing replacement.
I rotate tires on my car at each oil change, but to do so with a motorhome adds a considerable cost to the service procedure. I think it all comes down to how much does it cost to rotate tires on a Solera M/H vs. how much to replace with new tires.
I haven't done it yet but my intention is to get the dually valve stem kit but get shorter straight stems (around 2.5 to 3 inch) and use them on the front as well as inner rear. That will allow for rotating tires without changing the stems. I don't mind using a trucker style gauge for checking the pressure.
I'm of the opinion that rotation is important to tire life. I'm also a believer in following manufacturers recommendations.
My '15 Solera 24s was driven from the factory to the dealership in Oregon with 28 lbs of air in the inside rear duallies. The plastic Air-Flex extensions the came with it didn't properly seat or connect to the shrader valve preventing me from adding or measuring air pressure. I learned this only after driving it home. Of course, who checks tire pressures when buying a new RV? I went for the expensive steel extension solution. Enough on that topic.
My Continental tires are marked for 80 PSI while the motorhome is labelled for 60 PSI. I consider heat to be the most significant tire enemy. I use a Harbor Freight sourced non-contact, infrared thermometer to check tires whenever I stop for fuel or rest stop. I'm running the 80 pounds recommended on the tire. On a 80 degree day, the shade side tires run in the high 95 + or - degree range while the sunny side tires about 20 degree warmer (115 + or -). I'm happy with the 80 PSI and notice little if any change in handling or ride comfort. If a tire begins to lose pressure, the temperature will difference will be noticeable. Takes less than a minute to check all six tires.
As far as tire rotation, I would simply inspect the tires for tread depth and any unusual wear pattern along the edge. As far as I can figure, the rear tires carry about 7,000 lbs while the front carry about 3,500. The load per tire is pretty much equal and unless one takes corners at silly speeds, the wear on all the tires should be about the same negating the need for rotation.
One more comment about after market TPMS. The sensors on the end of each valve weight about 13 grams. Spinning at high speeds, those 13 grams exert alot of force on the valve stem base. The vendor(s) usual recommend metal stems BUT do not explicitly state they're required.
The photos show what happened to one of my rubber valve stems with 16k miles on it after only 200 miles with a TPMS Sensor. The others show the location of the new steel extensions on the duallies and the the kit itself. Also, I cannot attach aftermarket TPMS sensors to the installed, highly regarded metal stem - there is insufficient space to screw them on.
PS: The failed valve stem was from my Dodge Cummins pick up, not the Solera.