TST TPMS

CJW8 wrote:
cmeed,
Maybe you got lucky but comparing a tire gauge to a compressor gauge that is constantly vibrating does in no way prove accuracy.

I didn't know that tire shops had a certified master gauge but if they do, that means it had been verified against a dead weight tester or some other standard that has also been certified. The calibration instrument's certification can be traced all the way back to some national or international standard.

If my TPMS sensors are advertised to be +-1.5 PSI, that means there is a potential difference of 3 PSI between the highest and the lowest sensor. I went to NAPA and bought a quality tire gauge, the larger one like the truckers use. With it, I set all my tires at 80 PSI. Then I installed my TPMS sensors. They read between 79 and 81 PSI. I called it good enough.

I fabricated an adapter with a quick connector on one side of a nipple and a metal valve stem on the other end. Built up compressor to 80 psi shut it off and compared readings.

I have 4 Accutire digital gauges that all agree within 1/2 PSI. All of my TST507 sensors read about 3 PSI lower. One of these systems has a serious calibration error from the factory.

Dutch, Thanks, I stand corrected. The range is about 1.5 PSI

TST sensors are spec'ed at + or - 0.73 psi. Mine are all within a pound of the truck shop master gauge I checked them against.

cmeed,
Maybe you got lucky but comparing a tire gauge to a compressor gauge that is constantly vibrating does in no way prove accuracy.

I didn't know that tire shops had a certified master gauge but if they do, that means it had been verified against a dead weight tester or some other standard that has also been certified. The calibration instrument's certification can be traced all the way back to some national or international standard.

If my TPMS sensors are advertised to be +-1.5 PSI, that means there is a potential difference of 3 PSI between the highest and the lowest sensor. I went to NAPA and bought a quality tire gauge, the larger one like the truckers use. With it, I set all my tires at 80 PSI. Then I installed my TPMS sensors. They read between 79 and 81 PSI. I called it good enough.

I had accumulated a bunch of pencil gauges over the years and finally compared them to the air gauge on my 80 gal shop compressor. None were close so I threw them away and bought the best gauge from Oreilly and it matches my compressor gauge. My new air gauge matches my TST 507 +/- 1 lb.

Since neither is certified, neither can be considered more "accurate." However, both are "close enough."

I air mine up till the TST says they are right because the TST is the one that will do the alarming.

Impossible to tell from the information you've provided. Go buy a couple and use the one that agrees with your TPMS. :) Only half kidding. Mine has proven to be very accurate according to the gauges I use.

If you REALLY need to know which (if either) is exactly right, call around your local tire shops and see which one has a certified master gauge. Check your TPMS and handheld gauge readings against that.

Probably every gauge will be slightly different. I'd use the TPMS psi since it will alert if needed.