Longacre Pro Precision Tire Gauge
The Cobalt SS/SC Passenger Side Front Tire
The passenger side front tire on the Cobalt registered at exactly 31 PSI with the parts store tire gauge. The Longacre Pro Precision Tire Gauge read 31.25 PSI. This time, only a quarter-PSI separated the two. I attribute this to the inconsistency of the seal I got with the parts store gauge.
Sadly, my old tire gauge is only five years old, but it both struggles with sealing on tire stems and it quit holding pressure readings a few years ago.
I also checked the temperature with the Craftsman IR Pyrometer. The tread sat at 66.7°F — one half-degree difference between the two tires. Using my understanding of the Ideal Gas Law, I used the Ryobi Dual Function Inflator/Deflator and Longacre Tire Gauge to set the pressure to 32 PSI.
FYI, there was no difference to the ease with which the gauge worked between this tire and the first.
Why no difference in tire pressure? As mentioned above, the half-degree lower temperature means the tire pressure in this tire is less than 1/10th of a PSI different from the first — not only is it out of the half-PSI adjustment range I set for this test, above, it isn't easy to adjust for, nor is it necessary to be that accurate in my experience. Photo: Ryan King, 2019.
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