Paul in Houston TX:
Been using the 'new' gauge for two days now, and must say rides in my wife's car and mine are much firmer and a little bumpier. With the old gauge I was putting
32-34PSI into our tires, but now even 31-
32PSI is hard. I think this gauge is at least a little closer to 30PSI actually being 30PSI, and will continue to experiment.
The main purpose of a big round clock gauge is to get all four tires to read exactly the same PSI - whatever is chosen - 30, 33, etc, PSI. Most pencil-style gauges do not allow this level of precision, which is why lots of drivers complain of their vehicles "pulling" to one side, or of the steering reaction not being the same to right as it is to the left. Come to find out they have as much as 5-10psi difference between all four tires!
Having all four be within 1lb PSI of each other makes a load of handling difference and predictability. Of course, cars with different recommended front and rear pressures need to be set accordingly.