Originally Posted by overlander63
Most tire gauges are supposed to be accurate within 1 PSI. In most tire shops, all tire gauges are supposed to be checked for accuracy to a master gauge that has been calibrated. In the real world, of course, it doesn't happen. Just remember that a tire gauge is supposed to give you an idea of how much pressure is in your tires. I have a tire inflator/gauge that is 1 psi low, and another that is 10 psi high.
We used a gauge that was very repeatable, but off by 4 psi years ago when kart racing. It gave us an advantage when our competitors borrowed it...
We did check its repeatability on a regular basis.