Radial Tire Valve Core Failures

I run my Toyo tires at 90 psi. I'm weighing in at 21,200 pounds GVW.
You did not say whether you have extenders. I do, and would not be happy without them. That being said, I had a tire installer put a nylon stem on my prior Coachmen, and it got spit out like a watermelon seed.
Long way around to ask why so much pressure?

I've had the same cores since 2013, 110psi.

I suspect your tires have some sort of balancing stuff in them, causing the cores to not fully close.

Richard

I run 105 also on the same size tire but I have never had a valve core failure.

I’m thinking you are over the valve cores max pressure. And why 105? Have you weighed the MH? I’m certain you don’t need to run over 80 psi. I run 75 per Michelin’s pressure/weight chart. My rear axle I run at 95 per the chart.

if you are getting the replacement from the same place you need to change. You need to order some high pressure valve cores and install them. If you have car/light truck ones , yes then they will fail.

I too run over 100 lbs and not have a leak in many years. I do keep a pack of high pressure valve cores on hand just in case. I also put them in my other vehicles.

just look in my book and low pressure cores are good to 60 lbs and high pressure ones are good to 300. The ones I use on Vehicle /home air condition system are at 600. You could be getting them for the lower pressure of 60.

I'll stay tuned as this doesn't pass the smell test. A core failure every 6 months would mean that whatever the cause would very quickly have no sales and be a non product. Wonder how many OTR trucks with their high pressure tires have core failurs every 6 months?

Do you have beads, extenders or something else?

I've run 120 psi on my Toyo steer tires since 2011 with no failure. Do 90 psi duals qualify as high pressure? BTW IMHO many tire stores know little about larger tires including RV tires other than their lips are moving.