I called TST when I installed mine on the Reflection. They told me that "the added weight causes the rubber stems to flex too much which could lead to premature failure of the stem". They definitely wanted me to switch to metal stems. I took the FW to Discount Tire and they switched the stems and balanced the tires for a reasonable amount. They also put each tire/rim into a water tank to make sure there were no leaks before reinstalling them on the coach.