I have only used it on the car thus far and the gauge and the tire readout matched to within 1 PSI. I still need to perform the same operation on the truck. The pressures on the truck are more than double the car. I'll certainly post those results when I get them. Maybe tomorrow. My last test will be to add the TST 507 sensors to the coach and run the tires up to 110 PSI and see how that matches up.
I want to note that I ordered the Milton S-577A on Amazon. However they shipped the more expensive S-578A. The only difference I can tell is that the dual chuck on the 578 has both ends offset where the 577 chuck has one end inline and the other end is offset.
My only "complaint" is that I need to wear my cheaters to read the gauge when I'm setting a odd numbered pressure because the gauge uses 2 PSI increments. It's hard to read between the lines.
