So, we were happily driving from Chandler, AZ down to Tucson to do some camping with our daughter in her 400 (her Youtube channel is Amelia Away if any of you want to follow her travels). We were in the right lane and a semi was passing us and something got louder. We thought "that semi has a weird noise". A second later, our low tire sensor started beeping rapidly. Uh oh. Pulled off to the side of the road and found the left side (facing the travel lanes - why is it always that way) was blown out and water was pouring out of the Alde cold water drain. Uh oh again. Managed to get the tire changed with the spare after fooling around with a couple jacks. Pulled off at the next exit which would have been too far to nurse the camper to on the flat and assessed the underside. No obvious damage to the wheel well or surrounding structure. Phew. Went inside the camper (Max S - What is called a 320 now) and looked in the Alde compartment. No damage. Phew again. The vibration from the tire going flat must have vibrated the release valve up. Push it down and now that we are at the campsite, all is good. No leaks. Called a Discount Tire near the campground and they worked us in. We were in and out in a little over an hour. Great service. We replaced all three tires to make sure all was good. We camp a lot so this was good for peace of mind.
Some thoughts.
Bottle jack. A while ago, I bought a small bottle jack so it would fit under the frame with the tire flat. Guess what? For a 320 (not sure on the 400), If your bottle jack is small enough to fit under the frame when the tire is flat, it is nowhere near big enough to lift your trailer high enough to get the tire off. If you are relying on a bottle jack, test it by letting the air out of a tire and see if it fits and lifts high enough.
Don't just assume the jack in your tow vehicle will work. The scissor jack in our jeep was too tall to get under the frame with the flat.
Buy a scissor jack. One that collapses down very low but still has enough up travel. These typically have more "throw" than a bottle jack.
Hindsight, I thought about but didn't use the method of unhooking the camper, lowering the nose all the way, dropping the rear corner legs down then raising the nose. Figured it would have been a huge pain to do that but, in reality, would have been much easier and much more stable. As it was, I used our bottle jack to get it high enough to get the Jeep's scissor jack under the frame. Then I jacked it up the rest of the way.
Test your jack. The release valve on my bottle jack needed persuasion to release when it was no longer needed. A jack will do you no good if it does not work.
Weirdest part was that the inner inch of the tire tread had come off and wrapped itself around the axle. Had to do some yanking and threading to get it out. Safety first of course so I put the spare tire on the ground under the frame.
And the biggest thought. ALWAYS USE TIRE PRESSURE SENSORS. Had that not gone off, it would have probably taken us longer to recognize the issue. We were being passed by a semi so we though that was what was happening. Had we continued on for even another minute, the tire could have come apart more and done serious damage to the camper. I've seen horror stories of this. Get one that shows pressure and temperature and alarms with variances. If a tire is getting too hot, it is probably failing and it can blow. If you lose pressure slowly and don't know it, it can blow. I think ours was a rapid blowout since it was just a couple seconds between the odd sound and the sensor going off. The tires had lots of tread and no odd wear. Some sort of rapid failure or we ran over something.
Be prepared. I know some just use AAA and other services, but for those that don't, make sure you tire changing solution will work. Don't just assume. Like I said above, let the air out of one of your tires and make sure you can change that tire with what you have.