Tire failures when towing are unfortunately not uncommon. With this information, I have not only made tire maintenance and attention a high priority in all of our travels since we bought our first RV 5 years ago. Furthermore, I also assume that is a matter of not if, but when it will occur and still can only keep my fingers crossed that such an event can be remedied safely without significant damage to persons or things. Part of my preparedness is the utilization of a TPMS sensor system which many cars have had as standard equipment for decades, but these systems are designed specifically for towing and the additional range of the sensor/transmitter is capable of reaching from the trailer axles to the cab of the truck. Once a preset limit (high or low) is reached on a particular tire, it sounds an alarm which up until the ride home from Williamsburg, VA I had not heard in earnest before.
We were traveling in tandem (since Kris and I drove separately) so she called me quickly when I quickly pulled off the road. Thankfully there was a decent shoulder at that particular spot on 301 between Upper Marlboro and Bowie for me to assess the situation. The right rear tire of the RV was indeed significantly low on air pressure. While I tried to assemble a plan, Kris headed a little further down the road to see if there was a safer spot to change the tire and thankfully there was a wide driveway for business that I could pull into. The offending tire was still holding about 25psi, so I limped the quarter mile to the safer spot to swap out the tire for the spare which only took me about 25 minutes. The majority of that time was spent locating what I needed.
Upon closer inspection when we got home, I couldn’t find a fault with the tire. I managed to re-inflate the tire back up to 75 psi. “What gives?” by happenstance, when I was disconnecting the air chuck, I heard a brief hiss and then it started coming together for me. If I pressed the valve stem just right… air would rush out of it. This then points to the valve stem being at fault rather than anything wrong with the tire at all. The centrifugal force of the weight of the TPMS sensor, which screws onto the end of the stem, had separated the brass stem insert from the rubber grommet that is friction fit into the wheel. Ugh… easy fix thankfully: I’ll merely replace the rubber stem with a fixed metal stem like trucks would have.