If you get a Class A or Class C, you will have dual wheels in the rear. This causes the issue of....... "um...... how do I put air in the inside tires????"
The answer is.... VALVE EXTENDERS.
However, the dealers won't put them on correctly. The dealers just take your hubcaps off, screw them in, put the hubcaps back on, WHAM BAM that's it. Well, you could do that yourself! But.... there is one problem to that. You put them on that way, well, they flop around while you are driving, and they eventually start leaking.
You need to have the extenders anchored to your hubcaps.
So far, over here in the West, Les Schwab Tire Center is the only ones who will do it that way. However, Les Schwab won't achor extenders put on somewhere else. They will only anchor their own. Les Schwab's tend to be in smaller towns.
On my second RV, I had extenders put on by the dealer. They started leaking. I had one set go bad (driver's side). I went to a Les Schwab, they put new ones on and anchored them down. Then, the passenger side went bad. I was out of town, found a Les Schwab, and they put new ones on and anchored them.
Ok, my current RV came with extenders already on. I just went to Les Schwab and got them replaced anyway. I didn't want to be travelling and have one go bad and have to hunt down a Les Shwab then.
So, if you get a new or used RV and you are in the West, even if they come with extenders, just go to Les Schwab and get the whole thing replaced and done right.