TPMS question
I work in production in a medium-seized body shop. Recently, we had an Impala come in with some aftermarket wheels that were damaged. We ordered the replacement wheels from a local vendor, and to my alignment shop's surprise, the wheels had 2 valve stem holes in them. I called up my vendor, and he said this was very common ("Industry standard") on new a/m wheels, and that the extra hole is for a TPMS sensor. These sensors break, he said, during the tire mounting process in a typical valve stem location, so an auxillary one was machined into the wheels. It was in an impractical filling location for an air chuck, so they cut a second hole. It makes perfect sense, but this particular Impala did not come with those sensors from the factory.
The question comes here. Both the vendor and his distributor said to run two valve stems per wheel. Although this seems like the correct thing to do (seeing as the TPMS sensors are basically valve stems themselves), is this a safe procedure? My insurance company rep, my alignment shop, and myself all wanted the vendor to release some documentation stating that this is the correct procedure, but he refused and defected to the manufacturer's warranty. I just wanted to know if this procedure is as common as he claims, and if this really is a new trend in the industry that I will have to remember in the future.