I have had a continuing problem with an inside dual tire losing air. At times the problem also manifested itself as virtually impossible to get added pressure into the tire, topping out around 80 psi.
On a recent trip I found the pressure to be 74 psi. A tire dealer identified the problem as being the extension schrader valve. He worked on the o-ring seal, reinstalled it and aired to the 90 psi. Next morning, in Raton, I decided with reluctance of what I might find, to check the pressure. Back to 74 psi. Nuts. This time went to a different tire dealer, Cunico Tire, Raton , NM, and very easy access (575-445-3473). He removed the supposedly repaired extension, installed a new one that uses....he says....a much better o-ring type of seal. And it has been great! ---after two years of messing with this thing with Herman Power. Thanks Cunico.
I put a picture below of the extension in case a newbie may not know what I am talking about.....uses one schrader valve to press a rod down inside a tube to press the schrader valve on the tire and allow air in, and out. I attempted a photo of the inlet schrader valve on the extension.
SO...if you are losing some air on an inside dual AND you use this type of air valve extension, it may be something to examine.
I took my extensions off and threw them in the garbage. Its safer without them. I bought a straight tire filler with a built in gauge,
problem solved
Zero issues with the extensions since my tire guy put the supports in the outside rim for the extension
I run the crossfire dual filler/monitor things.
On my GV I had those 4in metal extensions and one of them managed to shear off the wheel valve at the threads on the wheel end and gave me a dead flat. Never again will I fit any extensions. My tire monitor saved the day and the cost of a new tire.
I have seen the flexible ones with the support in one of the outer wheel holes and they "may" work but a trucker said they leak.
Speedbird 1