My 2021 GMC Sierra 3500HD came with the factory trailer TPMS system. I have long wanted to install these on my 5th wheel and finally got around to doing it. My 5ver has G rated 110psi tires on it and when I first took it to Discount Tire to have the GM valve stems installed they told me that the GM valve stems were too small. The rim hole size on the trailer were .625, much larger than the supplied stems from GM. So I went home with my tail between my legs.
I did some research online and found a company in Arizona that makes the larger stems that will take the GM sensors. The company is Nichols Manufacturing(link below). You can send them your originals and they will send you new ones, or you can buy new ones, swap the sensors, and return the old stems to them as a core charge. I sent them the cores and they quickly sent back the new diameter ones. Installing the sensor on was quick and I returned to Discount Tire to have them put on.
Installation went smoothly at DT with the only hiccup being that their air lines are only capable of getting to 90 psi so when I returned home I had to inflate the tires back up to the 110psi they run at. Pairing the sensors to the truck was simple enough and DT took care of that for me.
It is extremely nice having the integrated system in the truck and not having to have a separate unit mounted somewhere on the dash or windshield.
Thanks to the team at Discount Tire and Nichols Manufacturing for helping getting me up and going.